SF240E - NEC Electronics

SEFUSE

THERMAL CUTOFF

8th Edition

Cutaway View of SEFUSETM

SF Type

SEFUSETM

Contents

Introduction .....................................................................................................................................4

Features............................................................................................................................................4

Applications .....................................................................................................................................4

Product Types ..................................................................................................................................5

Operating Principle .........................................................................................................................6

Drawings, Dimensions and Marking .............................................................................................7

Standard Ratings.............................................................................................................................8

Performance Data..........................................................................................................................11

Lead Cutting and Taping...............................................................................................................15

Cautions .........................................................................................................................................16

Application Examples ...................................................................................................................21

Series Rated Current Rated Functioning Temperature Page

SF / E 10 Aa.c. 73 ˚C to 240 ˚C 8

SF / Y 15 Aa.c. 73 ˚C to 24C ˚C 8

SM / A 2 Aa.c. 70 ˚C to 187 ˚C 9

SM / B 1 Aa.c. 100 ˚C to 150 ˚C 9

SM / G 0.5 Aa.c. 100 ˚C to 150 ˚C 9

Select optimum series according to temperature and electrical ratings.

Please be sure to read the "Cautions" on pages 16 through 19 before using.

Introduction

NEC's SEFUSETM is a compact and reliable thermal cutoff designed to protect domestic electrical

appliances and industrial electrical equipment from fire. Cutoff occurs and an electrical circuit opens

when ambient temperature increases to an abnormal level.

Two NEC SEFUSE types are available. The SF type uses an organic thermosensitive material as the

thermal pellet and its operating temperature range is 73 ˚C to 240 ˚C.

The SM type uses a fusible alloy and has an operating range of 70 ˚C to 187 ˚C.

SEFUSE is manufactured in Japan and thailand, and both factories are ceritified by the Interna-

tional Standards Organization (lSO) for the ISO9001 quality standard. The factory in Japan is certi-

fied for the ISO 14001 environmental management system too.

Features

●Compact, durable, and reliable by resin-sealed construction

●One shot operation

●Excellently sensitive to abnomal temperature rise and high accuracy in operation

●Stable and precise operation

●Wide choice of types to suit the application (SF or SM)

●Meets many international safety standards

Applications

●Electric heaters, electric irons, hair dryers, electric blankets

●Air conditioners, compressors, washing machines, electric fans, ventilation fans, electric pencil

sharpeners, electric sewing machines, copy machines, various motors

●Color televisions, LCD televisions, stereo equipment, Iamps, fluorescent lamps, electric shavers,

video and audio cassette recorders, various transformers, AC adaptor, charger, Battery packs

●Rice cookers, microwave ovens, electric refrigerators, electric water pots, toasters, electric pans,

coffee makers, juicers, dish dryers

●Gas boilers, gas heaters, oil heaters, cameras, telephone switching (PBX) equipment

Safety standards

Japan UL CSA VDE BEAB

Electrical Appliance and

Material Control Law of

Japan

Underwriters Laboratories

Inc. (U. S. A.) Canadian Standards

Association Verband Deutscher

Elektrotechniker e.V.

(F. R. G.)

British Electrotechnical

Approvals Board

SEFUSETM

Product Types

The SF type uses an organic thermosensitive pellet inside a metal case. It features a large cutoff

(rated) current of 10 A or 15 A.

The SM type uses a fusible alloy inside a ceramic case. It has a cutoff(rated)current of 0.5 A, 1 A or

2 A. Because of its insulated case, the SM type can be attached directly where temperature detec-

tion is required.

●SF Type

●SM Type

SF Type

SM Type

Operating Principle

THE SF type contains a sliding contact, springs, and a thermal pellet inside a metal case. When

spring B is compressed, firm contact between lead A and the sliding contact occurs. This presses

two disks against the sliding contact and the thermal pellet. At normal temperatures, current flows

from lead A to the sliding contact and then through the metal case to lead B. When the ambient

temperature rises to the SEFUSE operating temperature, the heat transferred through the metal

case melts the thermal pellet. When the thermal pellet melts, springs A and B expand, moving the

disk and sliding the contact away from lead A. The electrical circuit is opened by breaking contact

between the sliding contact and lead A.

In the SM type, Ieads A and B are connected by a conductive thermal pellet (fusible alloy). The

current flows directly from one lead to the other. The fusible alloy is coated with a special flux.

When ambient temperature rises to the SEFUSE operating temperature, the fusible alloy melts and

condenses into a drop around the end of each lead because of surface tension and the coating of

special flux. The electrical circuit then opens.

,,,

●

After Operation

●

Before Operation

Sealing

Compound Ceramic

Case Fusible

Alloy Sealing

Compound

Lead Lead

Fusible Alloy

Lead

Flux

Lead

,,,

● After Operation

● Before Operation

Sealing

Compound

Sliding

Contact Sliding

Contact Disks

Spring A Spring A

Spring B

Ceramic Pipe

Lead A

Ceramic Spring B Thermal Pellet Thermal Pellet

Lead B

Metal Case

Disks

SEFUSETM

SF Type

SM Type

Drawings Dimensions, and Marking

●

SM/A, SM/B Series Unit : mm

●

MARKING

●

SM/G Series

●

MARKING

MITI

Approved Mark

Brand Name

SEFUSE

SM126A0

Tf 131˚C

2A 250V~

Part Number

Production

Control No.

Rated Functioning

Temperature

Rated Current Rated Voltage

MITI

Approved Mark Brand Name

SEFUSE

110 G0

Tf 115˚C

0.5A 250V~

Part Number

Rated Functioning

Temperature

Rated Current

Production

Control No. Rated Voltage

Note: The dimensions for long lead devices are in parentheses.

SM/A

SM/B

0.6

2.5

85(145)

38(68) 38(68)

0.53

2.0

85(145)

39.5(69.5) 39.5(69.5)

0.53

1.6

85(145)

40(70) 40(70)

1.0

4.2

66(81)

20(35) 35

Note: The dimensions for long lead devices are in parentheses.

1.3

4.2

66(81)

20(35) 35

●

SF/E Series Unit : mm

●

MARKING

●

SF/Y Series Unit : mm

●

MARKING

MITI

Approved

Mark

Brand Name

SEFUSE

SF139E

Tf 142˚C

10A

250V~

Factory ∗

Code

Part Number

Production

Control No.

Rated Functioning

Temperature

Rated Current

Rated Voltage

MITI

Approved

Mark

Brand Name

SEFUSE

SF139Y

139˚C

15A

250V

Maker

Mark

Part Number

Production

Control No.

Rated Functioning

Temperature

Rated Current

Rated Voltage

∗ Factory Code represents the factory location as shown below.

Japan : none, Thailand : B

SF Type

●SF/E Series

Standard Ratings

Note : 1) Part numbers are for standard lead devices. For long leads, add the number “–1” at the end of part number.

2) The maximum temperature limit of SF226E is partially approved as shown below.

* Under application to increase to over 300˚C

3) The additional electrical ratings are recognized by UL and CSA as follows.

UL : 277 Vac / 15 Aac (Resistive), 240 Vac / 15 Aac (Resistive), 120 Vac / 15 Aac (Resistive, Inductive)

CSA : 250 Vac max. / 15 Aac max. (Resistive, Inductive)

4) SF169E, SF188E, SF214E, SF226E and SF240E are also UL-recognized of optional CH-rating

(Conductive Heat Aging Test).

5) The VDE recognized file number had been changed in February 1998. The number in parentheses are previous

file number.

Note : 1) Part numbers are for standard lead devices. For long leads, add the number “–1” at the

end of part number.

Rated Current Safety Standard

33–312

33–331

33–332

33–333

33–334

33–335

33–336

33–549

33–354

●SF/Y Series

Operating

Temperature

70±2 ˚C

76±2 ˚C

91±2 ˚C

96±2 ˚C

109±2 ˚C

119±2 ˚C

129±2 ˚C

139±2 ˚C

152±2 ˚C

169±2 ˚C

188±2 ˚C

214±2 ˚C

226±2 ˚C

237±2 ˚C

Rated Functioning

Temperature

73 ˚C

77 ˚C

94 ˚C

99 ˚C

113 ˚C

121 ˚C

133 ˚C

142 ˚C

157 ˚C

172 ˚C

192 ˚C

216 ˚C

227 ˚C

240 ˚C

Part

Number

SF 70Y

SF 76Y

SF 91Y

SF 96Y

SF109Y

SF119Y

SF129Y

SF139Y

SF152Y

SF169Y

SF188Y

SF214Y

SF226Y

SF240Y

Rated Voltage

15 A (AC) 250 V (AC)

TM.Tm UL CSA VDE BEAB

SF226E 240˚C ∗330˚C 300˚C 300˚C

Part

Number

SF 70E

SF 76E

SF 91E

SF 96E

SF109E

SF119E

SF129E

SF139E

SF152E

SF169E

SF188E

SF214E

SF226E

SF240E

Rated Functioning

Temperature

TF, Tf

73 ˚C

77 ˚C

94 ˚C

99 ˚C

113 ˚C

121 ˚C

133 ˚C

142 ˚C

157 ˚C

172 ˚C

192 ˚C

216 ˚C

227 ˚C

240 ˚C

Operating

Temperature

70±2 ˚C

76±2 ˚C

91±2 ˚C

96±2 ˚C

109±2 ˚C

119±2 ˚C

129±2 ˚C

139±2 ˚C

152±2 ˚C

169±2 ˚C

188±2 ˚C

214±2 ˚C

226±2 ˚C

237±2 ˚C

45 ˚C

51 ˚C

66 ˚C

71 ˚C

84 ˚C

94 ˚C

104 ˚C

114 ˚C

127 ˚C

144 ˚C

164 ˚C

189 ˚C

190 ˚C

150 ˚C

159 ˚C

172 ˚C

189 ˚C

300 ˚C

350 ˚C

Rated

Current

10 A

(AC)

Rated

Voltage

250 V

(AC)

Safety Standard

UL CSA VDE BEAB

52330

E71747 C0632

6778.2

–1171

–0002

6778.2

–4510

–1008

33–312

33–331

33–332

33–333

33–334

33–335

33–336 33–886

33–549

33–354

33–835

33–834

33–833

33–832

33–831

33–830

33–827

33–828

made in

Japan made in

Thailand

2) 3)

SEFUSETM

SM Type

Part

Number

SM065A0

SM095A0

SM110A0

SM126A0

SM130A0

SM145A0

SM164A0

SM182A0

Rated Functioning

Temperature

TF, Tf

70 ˚C

100 ˚C

115 ˚C

131 ˚C

135 ˚C

150 ˚C

169 ˚C

187 ˚C

Operating

Temperature

65±2 ˚C

95±2 ˚C

110±2 ˚C

126±2 ˚C

130±2 ˚C

145±2 ˚C

164±2 ˚C

182±2 ˚C

40 ˚C

65 ˚C

80 ˚C

96 ˚C

100 ˚C

115 ˚C

133 ˚C

152 ˚C

80 ˚C

115 ˚C

125 ˚C

140 ˚C

145 ˚C

160 ˚C

180 ˚C

195 ˚C

Rated

Current Rated

Voltage Safety Standard

UL CSA VDE BEAB 33–528

33–466

33–472

33–467

33–468

33–470

33–556

●SM/A Series

C0600

2 A

(AC) 250 V

(AC) E71747

6778.2

–1171

–0001

LR52330

Note : 1) Part numbers are for standard devices. For long leads, change the last number from 0 to 1.

Part

Number

SM095B0

SM110B0

SM126B0

SM130B0

SM145B0

Rated Functioning

Temperature

TF, Tf

100 ˚C

115 ˚C

131 ˚C

135 ˚C

150 ˚C

Operating

Temperature

95±2 ˚C

110±2 ˚C

126±2 ˚C

130±2 ˚C

145±2 ˚C

65 ˚C

80 ˚C

96 ˚C

100 ˚C

115 ˚C

125 ˚C

140 ˚C

145 ˚C

160 ˚C

Rated

Current Rated

Voltage Safety Standard

UL CSA VDE BEAB 33–466

33–472

33–467

33–468

●SM/B Series

C0557

1 A

(AC) 250 V

(AC) E71747

6778.2

–1171

–0004

6778.2

–4510

–1009

LR52330

Note : 1) Part numbers are for standard devices. For long leads, change the last number from 0 to 1.

∗ Tm of SM145B for CSA is 155 ˚C

Part

Number

SM095G0

SM110G0

SM126G0

SM130G0

SM145G0

Rated Functioning

Temperature

TF, Tf

100 ˚C

115 ˚C

131 ˚C

135 ˚C

150 ˚C

Operating

Temperature

95±2 ˚C

110±2 ˚C

126±2 ˚C

130±2 ˚C

145±2 ˚C

65 ˚C

80 ˚C

96 ˚C

100 ˚C

115 ˚C

125 ˚C

140 ˚C

145 ˚C

155 ˚C

Rated

Current Rated

Voltage Safety Standard

UL CSA VDE BEAB 33–466

33–472

33–467

33–468

●SM/G Series

C0743

0.5 A

(AC) 250 V

(AC) E71747 LR52330

Note : 1) Part numbers are for standard lead devices. For long leads, change the last number from 0 to 1.

2) The additional electrical ratings are recognized by UL as follows.

SM095G : DC 50 V / 3 A,

SM110G, SM126G, SM130G, SM145G : DC 50 V / 5 A

2) 2)

6778.2

–4510

–1007

( )

∗

6778.2

–1171

–0003

6778.2

–4510

–1005

( )

#) The VDE recognized file number had been changed in February 1998. The number in parentheses are previous

file number.

(

)

Definition of Terms

●Rated Functioning Temperature

Rated functioning temperature is the operating temperature of thermal cutoffs, measured using

the method specified in the safety standard. In present E.A.M.C. (Electrical Appliance and Material

Control) Law of Japan, Valid until June 2001, the operation should be within the specified oper-

ating temperature range of ± 7˚C. In various standards such as UL, CSA, VDE, BEAB and new

E.A.M.C. Low of Japan, which comply with the IEC standard, it is called the rated functioning

temperature, and should operate within the prescribed temperature range of +0/–10 ˚C.

It is represented by the symbol TF in the UL standard, and by the symbol Tf in the CSA, VDE and

BEAB and new E.A.M.C. standards.

In SEFUSE, a temperature that complies with both standards is set as the rated functioning

temperature, and is indicated on the body of the thermal cutoff.

●Operating Temperature

Operating temperature is the actual operating temperature range when the thermal cutoff is

made to operate inside a constant temperature oven whose temperature is raised at the rate of

1 ˚C/min. while a detection current of 100 mA or lower is applied.

The operating temperature is a standard set by NEC and is not specified by a safety standard.

●TH, Th, Tc (Holding Temperature)

Holding temperature is the maximum temperature at which, when applying a rated current to

the thermal cutoff, the state of conductivity is not changed during specified time not hess than

168 hours (1 week).

It is represented by the symbol TH in the UL standard, Th in the CSA standard, and Tc in the VDE,

BEAB and new E.A.M.C. standards.

●TM, Tm (Maximum Temperature Limit)

Maximum temperature limit is the temperature up to which thermal cutoffs will not change its

state of cutoff without impairing.

It is represented by the symbol TM in the UL standard and by Tm in the CSA, VDE, BEAB and new

E.A.M.C. standards.

●Rated Current

Reted current is the maximum current that thermal cutoffs allow to carry and are able to cutoff

the circuit in safety.

●Rated Voltage

Reted voltage is the maximum voltage that is allowed to apply to the circuit in wich the thermal

cutoff is used.

SEFUSETM

SF/E & SF/Y Series Performance Data

SF/E

Temperature Rise (˚C)

Temperature Rise Response Time

High Temperature Storage TestInitial Characteristics

Temperature Difference (˚C)

(oil temp. minus operating temp.)

Time for opening after immersion

into oil (seconds)

Pass-through Current (A)

SF/Y

(˚C)

10 15 20

20 30 4010

SF169E

SF169Y

SF139E

SF139Y

SF109E

SF109Y

SF96E

SF96Y

SF70E

SF70Y

Part

Number

SF169E

SF169Y

SF139E

SF139Y

SF109E

SF109Y

SF96E

SF96Y

SF70E

SF70Y

Part

Number Time (Hours)

Operating

Temperature

(˚C)

Insulation

Resistance after

Operation

(MΩ)

Change of

Operating

Temperature

(˚C)

Withstand Voltage

after Operation

(kV)

Internal

Resistance

(mΩ/25 mm)

169

167

168 2.0

1.0

1.5 1.5 E@140˚C

@119˚C

@89˚C

@76˚C

@50˚C

0.5

1.0

–2

140

138

139 2.0

1.0

1.5 1.5 E

0.5

1.0

112

110

111 2.0

1.0

1.5 1.5 E

0.5

1.0

96 2.0

1.0

1.5 1.5 E

0.5

1.0

70 2.0

1.0

1.5 1.5

0 10 100 1,000 10,000

0.5

1.0

–2

Note : The values following @ are the storage temperature.

SM/A Series

,,,

,,,,,

,,,,

,,,

,,,,

,,,,,,

,,,,,

(˚C)

SM095A0

SM110A0

SM126A0

SM130A0

SM145A0

SM095A0

SM110A0

SM126A0

SM130A0

SM145A0

Temperature Rise (˚C)

Temperature Rise Response Time

High Temperature Storage TestInitial Characteristics

Temperature Difference (˚C)

(oil temp. minus operating temp.)

Time for opening after immersion

into oil (seconds)

Pass-through Current (A)

10 20 30 40 500

Part

Number

SM130A0

Part

Number Time (Hours)

Operating

Temperature

(˚C)

Insulation

Resistance after

Operation

(MΩ)

Change of

Operating

Temperature

(˚C)

Withstand Voltage

after Operation

(kV)

Internal

Resistance

(mΩ/25 mm)

146

145

144

3.4

3.0

2.6

SM145A0

SM126A0

SM110A0

SM095A0

SM130A0

SM145A0

SM126A0

SM110A0

SM095A0

3.0

2.0

1.0

131

130

129

4.4

4.0

3.6

3.0

2.0

1.0

127

126

125

4.4

4.0

3.6

3.0

2.0

1.0

111

110

109

4.4

4.0

3.6

3.0

2.0

1.0

3.0

2.0

1.0

0 10 100 1,000 10,000

@75˚C

–5

@90˚C

–5

@106˚C

–5

@110˚C

–5

@125˚C

–5

Note : The values following @ are the storage temperature.

SEFUSETM

SM/B Series

,,,

,,,,,

,,,

,,,,,

,,,,

,,,

123

SM095B0

SM110B0,SM126B0,SM130B0

SM145B0 SM095B0

SM110B0

SM125B0

SM130B0

SM145B0

Temperature Rise (˚C)

Temperature Rise Response Time

High Temperature Storage TestInitial Characteristics

Temperature Difference (˚C)

(oil temp. minus operating temp.)

Time for opening after immersion

into oil (seconds)

Pass-through Current (A)

10 20 30 40 500

Part

Number

SM130B0

Part

Number Time (Hours)

Operating

Temperature

(˚C)

Insulation

Resistance after

Operation

(MΩ)

Change of

Operating

Temperature

(˚C)

Withstand Voltage

after Operation

(kV)

Internal

Resistance

(mΩ/25 mm)

146

145

144

4.0

3.5

3.0

SM145B0

SM126B0

SM110B0

SM095B0

SM130B0

SM145B0

SM126B0

SM110B0

SM095B0

3.0

2.0

1.0

130

129

128

4.7

4.6

4.5

3.0

2.0

1.0

127

126

125

4.8

4.6

4.4

3.0

2.0

1.0

112

111

110

4.7

4.6

4.5

3.0

2.0

1.0

9.5

9.0

8.0

3.0

2.0

1.0

0 10 100 1,000 10,000

@75˚C

–5

@90˚C

@106˚C

@110˚C

@125˚C

–5

Note : The values following @ are the storage temperature.

SM/G Series

,,,

,,,,,

,,,,,,,

,,,,,,,,

,,,,,,

,,,,

,,,,,

,,,,

123

SM095G0

SM145G0

SM110G0

SM125G0

SM130G0

SM095G0

SM110G0

SM126G0

SM130G0

SM145G0

Temperature Rise (˚C)

Temperature Rise Response Time

High Temperature Storage TestInitial Characteristics

Temperature Difference (˚C)

(oil temp. minus operating temp.)

Time for opening after immersion

into oil (seconds)

Pass-through Current (A)

10 20 300

Part

Number

SM130G0

Part

Number Time (Hours)

Operating

Temperature

(˚C)

Insulation

Resistance after

Operation

(MΩ)

Change of

Operating

Temperature

(˚C)

Withstand Voltage

after Operation

(kV)

Internal

Resistance

(mΩ/25 mm)

146

145

144

5.0

4.0

3.0

2.0

1.0

@125˚C

SM145G0

SM126G0

SM110G0

SM095G0

SM130G0

SM145G0

SM126G0

SM110G0

SM095G0

–5

131

130

129

6.0

5.0

4.0

3.0

2.0

1.0

127

126

125

6.0

5.0

4.0

3.0

2.0

1.0

112

111

110

6.0

5.0

4.0

3.0

2.0

1.0

13.0

11.0

9.0

3.0

2.0

1.0

0 10 100 1,000 10,000

@110˚C

–5

@106˚C

–5

@90˚C

–5

@75˚C

–5

Note : The values following @ are the storage temperature.

SEFUSETM

Lead Cutting and Taping

reel

SWTT

L1L2

(75)

285

L1 : 7 to 30

L2 : 7 to 33 (mm)

SF type: 2000 pcs/reel

SM type: 2500 pcs/reel

L1, L2 : 7 to 33 (mm)

L2L1

● SF Type

Lead Cutting

● SF type : SF ∗∗∗E (only for lead cutting), SF ∗∗∗E-1

Does not apply to the SF/Y series.

● SM type : SM ∗∗∗A0, SM ∗∗∗B0, SM ∗∗∗G0 (short lead type)

NEC will perform lead cutting or taping as requested by customers.

Applicable Products

Taping

● SM Type

52±2

63±25±0.5 2.0 6±1 2.0 0.5 3.2 0.8

67±2

-L

TZRtS

(Unit : mm)

For more information on dimensions not described in diagrams above, please call NEC.

Cautions

This section describes cautions designed to protect the performance of the thermal cutoff. Be sure

to read and fully understand these cautions.

To obtain full performance from the thermal cutoff, it is necessary for the customer to

appropriately store the thermal cutoff, design appropriate circuits for the application, and

perform evaluations, mounting and testing as necessary. Problems arising from the

inappropriate execution of the above are the responsibility of the customer, and NEC declines

any and all responsibility.

Design Cautions

●Do not use this device for and purpose other than as a thermal cutoff.

The thermal cutoff is designed to detect abnormal rises in temperature and break circuits if

needed. It is not a current fuse that cuts excess current. If used as a current fuse, the SEFUSE

may malfunction.

●Do not use this device in aerospace equipment, aeronautical equipment, nuclear reactor control

systems, Iife support equipment or systems, transportation machinery engine control or safety-

related equipment.

This device is designed for use in household electric appliance, office automation equipment,

audio and video equipment, computer communications equipment, test and measurement

equipment, personal electronic equipment and transportation equipment (excluding engine

control).

●The customer should select the proper thermal cutoff device, mounting location, and mounting

method as appropriate for each application.

Verify whether the chosen selections are appropriate by repeatedly testing the final design for

thermal cutoff under normal conditions as well as under predicted maximum abnormal

conditions.

●Make designs so that the temperature of the body of the thermal cutoff does not exceed the

temperatures shown in Table 1.

If, the temperature is exceeded on a regular basis, the thermal cutoff may start operating only at

temperature lower than the normal operating temperature. Malfunctions may also occur. Even

if the thermal cutoff's operating temperature is exceeded, it may malfunction.

SEFUSETM

SM Type SF Type

Type Body Type Body

Temperature Temperature

SM065A 45 ˚C SF 70E, Y 50 ˚C

SM095A, B, G 75 ˚C SF 76E, Y 56 ˚C

SM110A, B, G 90 ˚C SF 91E, Y 71 ˚C

SM126A. B. G 106 ˚C SF 96E, Y 76 ˚C

SM130A, B, G 110 ˚C SF109E, Y 89 ˚C

SM145A, B, G 125 ˚C SF119E, Y 99 ˚C

SM164A 140 ˚C SF129E, Y 109 ˚C

SM182A 140 ˚C SF139E, Y 119 ˚C

SF152E, Y 132 ˚C

SF169E, Y 140 ˚C

SF188E, Y 140 ˚C

SF214E, Y 140 ˚C

SF226E, Y 140 ˚C

SF240E, Y 140 ˚C

●The body temperature of the thermal cutoff becomes higher as current passes through and

might rise higher than the ambient operating temperature (see test data). The temperature may

rise even higher depending on the mounting method and other conditions. Therefore, after mount-

ing the thermal cutoff under the same conditions you would use for the actual application, work

the final product and measure the body temperature of the thermal cutoff.

●Use the thermal cutoff with a voltage and current level lower than the rated level.

If the thermal cutoff is used with a voltage or current level higher than the rated level, contacts

may melt in the SF type, causing the fuse to malfunction. In the SM type, the body of the thermal

cutoff may be destroyed.

●Do not use the thermal cutoff in water, organic solvents or other liquids, or environments

containing sulfurous acid gas, nitrous acid gas, or high humidity. Doing so will cause

deterioration o f the sealing resin, the thermal cutoff may operate at lower than operating

temperature, or any other malfunctions may occur. Also, the thermal cutoff may not operate

even if its operating temperature is exceeded.

Table 1

Lead wire process

●When bending the lead wire, in order to protect the resin seal from excessive pressure, secure

the lead wire cIose to the case and bend the part beyond the secured section.

,,,

3 mmor more

SecuredSecured

0.8 steel wire

SF(10 kgf)

SM(5 kgf)

The lead wire should be bent at a distance 3 mm or more from the body of the fuse, and should

not be twisted.

●The tensile strength applied to the lead wire should be 5 kg or less for the SF type, and 1 kg or

less for the SM type.

●The strength applied to the body of the thermal cutoff should be 10 kg or less for the SF type, and

5 kg or less for the SM type.

In the case of an SF type, deformation of the case may change the location of the moving

electrode during operation and may cause the thermal cutoff to operate only at temperatures

lower than the normal operating temperature range. The thermal cutoff also may not operate

even if the thermal cutoff's operating temperature is exceeded.

Mounting

SEFUSE can be mounted by soldering, caulking, or welding.

●If soldering, note that the thermal cutoff may not function because of excessive solder

temperature.

To prevent such malfunctions, for example, holding the lead new the case by a tool is effective

for allowing the heat to escape, and the soldering should be done in short interval.

Another effective method is to use a lower solder temperature and to solder at a location that is

distant from the case.

●If caulking or welding, be careful to keep the resistance value of the connecting section low.

If the connecting section has a high resistance value, the passing current may generate an

abnormally high temperature that will cause the thermal cutoff to operate (break the circuit).

●It is recommended that the connecting position at the lead of resign-sealed side should be 5 mm

or more from the body of the thermal cutoff.

●After mounting the thermal cutoff, be careful not to apply force that may pull, push or twist the

lead wires.

●If using an SF type thermal cutoff, be sure not to make the lead on the resin-sealed side touch

the case. This would cause the current to flow from the lead on the resin-sealed side to the

opposite lead so that the thermal cutoff cannot break the circuit.

Note that the body of the SF type is the same in potential as the circuit. Therefore, it must be

electrically isolated from the other metalic part.

Storage

●The body and lead A of SF type, and the leads of SM164A and SM182A are silver-plated. There-

fore, these parts may discolor because of sulfuration. In the case, the marking of the body wiII

become difficult to discriminate or the solder -abiIity of lead wiII decline. To avoid this, the SEFUSE

should not keep around materials (such as cardboard or rubber, etc.) which generate sulfurous

acid gas.

●When the SEFUSE have to be storaged in a cardboard box, the SEFUSE's packs should be put

into other bags (such as polyethylene) and make sure the packs seal.

Recommendation

●Be careful when mounting the thermal cutoff because external force, heat, or a harmful atmos-

phere (containing excessive humidity or sulfurous acid gas) may damage the characteristics of

the thermal cutoff. If applicable, it is recommended to warn general consumers who are not

aware of the usage cautions for the thermal cutoff not to mount, remove or replace the thermal

cutoff through a note to this effect in the user's manual and other related material.

If you desire any clarifications or explanations regarding these cautions, please call an NEC

sales representative.

The values contained in this document were obtained under certain testing conditions at NEC.

They are not guaranteed and are for reference only.

5 mm or more 5 mm or more Connecting Position

5 mm or more Connecting Position

SEFUSETM

The information in this document is based on documents issued in February, 1999 at the latest. The

information is subject to change without notice. For actual design-in, refer to the latest publications of

data sheet, etc., for the most up-date specifications of the device.

No part of this document may be copied or reproduced in any form or by any means without the prior

written consent of NEC Corporation. NEC Corporation assumes no responsibility for any errors which

may appear in this document.

NEC Corporation does not assume any liability for infringement of patents, copyrights or other intellec-

tual property rights of third parties by or arising from use of a device described herein or any other

liability arising from use of such device. No license, either express, implied or otherwise, is granted

under any patents, copyrights or other intellectual property rights of NEC Corporation or others.

While NEC Corporation has been making continuous effort to enhance the reliability of its electronic

components, the possibility of defects cannot be eliminated entirely. To minimize risks of damage or

injury to persons or property arising from a defect in an NEC electronic component, customer must

incorporate sufficient safety measures in its design, such as redundancy, fire-containment, and anti-

failure features.

NEC devices are classified into the following three quality grades:

"Standard", "Special", and "Specific". The Specific quality grade applies only to devices developed based

on a customer designated "Quality assurance program" for a specific application. The recommended

applications of a device depend on its quality grade, as indicated below. Customers must check the

quality grade of each device before using it in a particular application.

Standard: Computers, office equipment, communications equipment, test and measurement equipment, au-

dio and visual equipment, home electronic appliances, machine tools, personal electronic equip-

ment and industrial robots

Special: Transportation equipment (automobiles, trains, ships, etc.), traffic control systems, anti-disaster

systems, anti-crime systems, safety equipment and medical equipment (not specifically de-

signed for life support)

Specific: Aircrafts, aerospace equipment, submersible repeaters, nuclear reactor control systems, life

support systems or medical equipment for life support, etc.

The quality grade of NEC devices is "Standard" unless otherwise specified in NEC's Data Sheets or Data Books.

If customers intend to use NEC devices for applications other than those specified for Standard quality grade,

they should contact an NEC sales representative in advance.

Anti-radioactive design is not implemented in this product.

SEFUSETM

Electric Iron Transformer

LCD Television Rice Cooker

Inverter for EL Light Drive

Remark(∗)

For the purpose of photography, the

insulation tube of the thermal cutoff

has been removed.

In reality , the thermal cutoff is covered

by the insulation tube.

Application Examples

Printed in Japan

For further information, please contact:

NEC Corporation

NEC Building

7-1, Shiba 5-chome, Minato-ku

Tokyo 108-8001, Japan

Tel: 03-3798-6148

Fax: 03-3798-6149

[Asia & Oceania]

NEC Electronics Hong Kong Ltd.

12/F, Cityplaza 4, 12

Taikoo Wan Road, Hong Kong

Tel: 2886-9318

Fax: 2886-9022, 2886-9044

Seoul Branch

10F, ILSONG Bldg., 157-37,

Samsung-Dong, Kangnam-Ku,

Seoul, The Republic of Korea

Tel: 02-528-0303

Fax: 02-528-4411

Shen-zhen Office

31st, Floor, Shen-zhen International Financial

Bldg. 23 Jian She Road, Shenzhen, China

Tel: 755-2227094

Fax: 755-2256360

Australia Representative Office

303-313 Burwoood Highway

Burwood East, Victoria 3151,Australia

Tel: 03-98878012/98878013

Fax: 03-98878014

NEC Electronics Taiwan Ltd.

7F, No. 363 Fu Shing North Road

Taipei, Taiwan, R.O.C.

Tel: 02-2719-2377

Fax: 02-2719-5951/5936

NEC Electronics Singapore Pte., Ltd.

101 Thomson Road

#04-02/05 United Square

Singapore 307591

Tel: 65-253-8311

Fax: 65-250-3583

1989(1997)

Document No. EM0060EJ8V1SG00 (8th edition)

Date Published February 1999 M

[North & South America]

NEC Electronics Inc.

Electron Components

2880 Scott Boulevard, M/S SC900

P.O.Box 58062

Santa Clara, CA 95052-2554, U.S.A.

Tel: 408-588-6160

Fax: 408-588-6130

(Regional Sales Offices)

Central Region

Greenspoint Tower

2800 West Higgins

Road Suite 765

Hoffman Estates, IL 60195, U.S.A.

Tel: 708-519-3930

Fax: 708-519-9329

Northern California Region

3033 Scott Blvd.

Santa Clara, CA 95054, U.S.A.

Tel: 408-588-5100

Fax: 408-588-5134

Eastern Region

901 N. Lake Destiny Drive

Suite 320

Maitland, FL 32751, U.S.A.

Tel: 407-875-1145

Fax: 407-875-0962

Western Region

One Embassy Centre

9020 S.W. Washington

Square Road

Suite 400

Tigard OR 97223, U.S.A.

Tel: 503-671-0177

Fax: 503-643-5911