PTC Thermistor for Overload Over-current Protection
Current Protection PTC Thermistor Description
Ceramic PTC (positive temperature coefficient) thermistors are used instead of conventional fuses to protect load, such as motors, transformers, or electronic circuit, against overcurrent for circuit protection. PTC thermistor protector not only respond to inadmissibly high currents but also if a preset temperature limit is exceeded. PTC thermistor over-current protector limits the power dissipation of the whole circuit by increasing their resistance and thus reducing the current to a harmless residual value. In contrast to conventional fuses, PTC thermistor resettable fuses do not have to be replaced after elimination of the fault but resume their protective function immediately after a short cooling-down time.
PTC Thermistor Over-current Protector Application
It applies in the over-current overload and short circuit protection of transformers, battery charger, switches, switch power supply, adaptor, meter, instrumentation, apparatus, electronic coils, control panels, air conditioner, automotive electron, etc.
Operating Principle of PTC Thermistor for Overload Over-current Protection
The operating principle is as indicated in the following. When a circuit is in the normal status, the current through PTC is lower than the rated current and PTC thermistor protector is in the normal state with small resistance value, which will not affect the normal operation of the protected circuit. In case of some fault in the circuit and the current is greater than the rated current, the PTC thermistor protector will become hot quickly and present a high resistance state, which sets the circuit relatively "off" to protect the circuit from damage. After the fault is removed, PTC thermistor protector will automatically restore its low resistance state and the circuit will resume normal operation.
Normally, when PTC thermistor is used as an overcurrent protection component, it is preferred to select maximum operating current, maximum operating voltage and proper specifications. Furthermore such factors should be taken into consideration as the dimensions of the components, rated zero-power resistance, operating temperature range, etc.
Relation between operating temperature, operating current and non-operating current is as shown in Fig.2. Operating current is normally 2~3 times non-operating current, and both of the currents will be reduced as
operating temperature increases.
Fig. 3 is Voltage-Current Curve and Load Curve in normal operating state. From point A to point B, the voltage on PTC thermistor protector increases gradually, current through PTC thermistor current limiting device also increases linearly, it indicates that PTC thermistor protector resistance keeps almost unchanged, in low resistance state; From point B to F, the voltage increases gradually, PTC thermistor protector resistance increases sharply due to heating, current through PTC thermistor current limiting device decreases rapidly, it indicates that PTC thermistor current limiting device in protection state. Normal load curve lower than point B, PTC thermistor over current protection device won't enter into protection state.
 |
Fig.2 PTC thermistor Non-trip current versus ambient temperature |
Generally PTC Thermistor protector carries 3 types over-current and overload protection.
1, PTC Thermistor for current overload protection(Fig. 4):RL1 is the loading current in normal operating state, When overloading resistance decreases, such as transformer short circuit, loading curve changes from RL1to RL2 , exceeding point B, PTC thermistor protector will enter into protection state.
2, PTC Thermistor for voltage overload protection (Fig. 5): Power voltage increases, such as increases abruptly from 220V to 380V, loading curve changes from RL1to RL2 , exceeding point B, PTC thermistor protector will enter into protection state.
3,PTC Thermistor for temperature protection(Fig. 6): When ambient temperature increases exceeding certain temperature, PTC thermsitor voltage-resistance curve changes from A-B-E to A-B1-F, loading curve RL , exceeding point B1, PTC thermistor protector will enter into protection state.
 |
| PTC Thermistor outline and dimension (mm) |
Examples of circuit protection using PTC Thermistor over-current protection devices
PTC Thermistor Protector Data Sheet
AMWEI PTC Thermistor for Overload Over-current Protection 265V/250V Series
| Part number |
Resistance
@25⊥
R25
(次)
|
Non-trip
current
IntㄗmAㄘ |
Trip current
@25⊥
It
(mA)
|
Max. operating
voltage
Vmax
(V)
|
Max. current
Imax
(A)
|
Reference
temperature
Tref
(⊥)
|
Dimension
(mm) |
| @25⊥ |
@60⊥ |
Dmax |
Tmax |
朴d |
| AMZ11-20P3R7H265 |
3.7㊣25% |
530 |
430 |
1050 |
265 |
4.3 |
120(P) |
22.0 |
5.0 |
0.6 |
| AMZ11-16P6R0H265 |
6.0㊣25% |
390 |
300 |
780 |
265 |
3.1 |
17.5 |
5.0 |
0.6 |
| AMZ11-16P7R0H265 |
7.0㊣25% |
350 |
280 |
700 |
265 |
3.1 |
17.5 |
5.0 |
0.6 |
| AMZ11-13P10RH265 |
10㊣25% |
260 |
200 |
520 |
265 |
1.8 |
14.0 |
5.0 |
0.6 |
| AMZ11-13P12RH265 |
12㊣25% |
225 |
180 |
450 |
265 |
1.8 |
14.0 |
5.0 |
0.6 |
| AMZ11-12P10RH265 |
10㊣25% |
250 |
200 |
500 |
265 |
1.8 |
13.5 |
5.0 |
0.6 |
| AMZ11-10P15RH265 |
15㊣25% |
180 |
140 |
350 |
265 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ11-10P39RH265 |
39㊣25% |
130 |
100 |
250 |
265 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ11-08P15RH250 |
15㊣25% |
150 |
120 |
300 |
250 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08P25RH265 |
25㊣25% |
130 |
100 |
250 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08P35RH265 |
35㊣25% |
115 |
90 |
225 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08P45RH265 |
45㊣25% |
105 |
80 |
200 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08P55RH265 |
55㊣25% |
90 |
70 |
180 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-07P82RH265 |
82㊣25% |
70 |
50 |
140 |
265 |
0.6 |
8.0 |
5.0 |
0.6 |
| AMZ11-07P56RH265 |
56㊣25% |
90 |
60 |
175 |
265 |
0.6 |
8.0 |
5.0 |
0.6 |
| AMZ11-06P33RH250 |
33㊣25% |
110 |
85 |
200 |
250 |
0.4 |
7.0 |
4.5 |
0.6 |
| AMZ11-05P70RH265 |
70㊣25% |
65 |
50 |
130 |
265 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-05P85RH265 |
85㊣25% |
60 |
45 |
120 |
265 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-05P39RH250 |
39㊣25% |
80 |
65 |
160 |
250 |
0.2 |
6.5 |
5.0 |
0.6 |
| AMZ11-05P121H265 |
120㊣25% |
45 |
35 |
90 |
265 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-05P181H265 |
180㊣25% |
40 |
30 |
80 |
265 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-04P70RH250 |
70㊣25% |
50 |
40 |
100 |
250 |
0.2 |
5.5 |
5.0 |
0.6 |
| AMZ11-04P121H265 |
120㊣25% |
40 |
30 |
80 |
265 |
0.2 |
5.5 |
5.0 |
0.6 |
| AMZ11-03P151H250 |
150㊣25% |
40 |
30 |
75 |
250 |
0.2 |
4.5 |
5.0 |
0.5 |
| AMZ11-10N12RH250 |
12㊣25% |
170 |
130 |
340 |
250 |
1.2 |
100(N) |
11.0 |
5.0 |
0.6 |
| AMZ11-10N18RH265 |
18㊣25% |
145 |
110 |
290 |
265 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ11-10N22RH265 |
22㊣25% |
125 |
90 |
250 |
265 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ11-07N22RH250 |
22㊣25% |
120 |
90 |
225 |
250 |
0.5 |
8.0 |
5.0 |
0.6 |
| AMZ11-05N151H265 |
150㊣25% |
38 |
30 |
80 |
265 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-05N301H265 |
300㊣25% |
27 |
20 |
55 |
265 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-05N601H265 |
600㊣25% |
20 |
15 |
40 |
265 |
0.2 |
6.5 |
5.0 |
0.6 |
| AMZ11-05N102H265 |
1000㊣25% |
15 |
12 |
30 |
265 |
0.2 |
6.5 |
5.0 |
0.6 |
| AMZ11-04N151H265 |
150㊣25% |
36 |
28 |
80 |
265 |
0.3 |
5.5 |
5.0 |
0.6 |
| AMZ11-03N151H265 |
150㊣25% |
33 |
25 |
65 |
265 |
0.2 |
4.5 |
5.0 |
0.5 |
| AMZ11-03N101H250 |
100㊣25% |
40 |
30 |
80 |
250 |
0.2 |
4.5 |
5.0 |
0.5 |
| AMZ11-03N70RH250 |
70㊣25% |
45 |
35 |
90 |
250 |
0.1 |
4.5 |
5.0 |
0.5 |
| AMZ11-08M12RH250 |
12㊣25% |
120 |
70 |
220 |
250 |
0.8 |
80(M) |
9.0 |
5.0 |
0.6 |
| AMZ11-08M25RH265 |
25㊣25% |
85 |
50 |
170 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08M35RH265 |
35㊣25% |
80 |
50 |
150 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08M50RH265 |
50㊣25% |
60 |
40 |
120 |
265 |
1.0 |
9.0 |
5.0 |
0.6 |
| AMZ11-07M101H265 |
100㊣25% |
50 |
30 |
100 |
265 |
0.6 |
8.0 |
5.0 |
0.6 |
| AMZ11-05M70RH250 |
70㊣25% |
50 |
30 |
100 |
250 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-05M121H265 |
120㊣25% |
30 |
20 |
60 |
265 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-03M101H250 |
100㊣25% |
25 |
18 |
55 |
250 |
0.2 |
4.5 |
5.0 |
0.5 |
| AMZ11-03M151H265 |
150㊣25% |
22 |
15 |
45 |
265 |
0.2 |
4.5 |
5.0 |
0.5 |
AMWEI PTC Thermistor for Overload Over-current Protection 140V Series
| Part Number |
Resistance
@ 25⊥
R25
ㄗ次ㄘ |
Non-trip
current
IntㄗmAㄘ |
Trip current
@25⊥
It
ㄗmAㄘ |
Max. operating
voltage
Vmax
(V) |
Max. current
Imax
(A) |
Reference
temperature
Tref
(⊥)
|
Dimension
ㄗmmㄘ |
| @25⊥ |
@60⊥ |
Dmax |
Tmax |
朴d |
| AMZ12-20P2R6H140 |
2.6㊣25% |
650 |
500 |
1300 |
140 |
4.3 |
120⊥(P) |
22.0 |
5.0 |
0.6 |
| AMZ12-16P4R7H140 |
4.7㊣25% |
425 |
330 |
850 |
140 |
3.1 |
17.5 |
5.0 |
0.6 |
| AMZ12-16P5R6H140 |
5.6㊣25% |
400 |
310 |
800 |
140 |
3.1 |
17.5 |
5.0 |
0.6 |
| AMZ12-13P6R8H140 |
6.8㊣25% |
325 |
250 |
650 |
140 |
1.8 |
14.0 |
5.0 |
0.6 |
| AMZ12-12P5R6H140 |
5.6㊣25% |
325 |
250 |
650 |
140 |
1.8 |
13.5 |
5.0 |
0.6 |
| AMZ12-12P6R8H140 |
6.8㊣25% |
300 |
230 |
600 |
140 |
1.8 |
13.5 |
5.0 |
0.6 |
| AMZ12-10P10RH140 |
10㊣25% |
225 |
170 |
450 |
140 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ12-10P6R8H140 |
6.8㊣25% |
275 |
200 |
550 |
140 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ12-08P22RH140 |
22㊣25% |
135 |
110 |
270 |
140 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ12-06P25RH140 |
25㊣25% |
125 |
90 |
250 |
140 |
0.5 |
7.0 |
5.0 |
0.6 |
| AMZ12-05P33RH140 |
33㊣25% |
90 |
70 |
175 |
140 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ12-16R2RIH140 |
2.1㊣25% |
710 |
570 |
1420 |
140 |
3.1 |
140⊥(R) |
17.5 |
5.0 |
0.6 |
| AMZ12-13R3R8H140 |
3.8㊣25% |
500 |
400 |
1000 |
140 |
1.8 |
14.0 |
5.0 |
0.6 |
| AMZ12-10R15RH140 |
15㊣25% |
210 |
170 |
420 |
140 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ12-10R6R7H140 |
6.7㊣25% |
300 |
230 |
600 |
140 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ12-10R10RH140 |
10㊣25% |
250 |
200 |
500 |
140 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ12-08R12RH140 |
12㊣25% |
200 |
160 |
400 |
140 |
0.6 |
9.0 |
5.0 |
0.6 |
AMWEI PTC Thermistor for Overload Over-current Protection 60V Series
| Part Number |
Resistance
@ 25⊥
R25
ㄗ次ㄘ |
Non-trip
current
IntㄗmAㄘ |
Trip current
@25⊥
It
ㄗmAㄘ |
Max. operating
voltage
Vmax
(V) |
Max. current
Imax
(A) |
Reference
temperature
Tref
(⊥) |
Dimension
ㄗmmㄘ |
| @25⊥ |
@60⊥ |
Dmax |
Tmax |
朴d |
| AMZ13-16P2R3H60 |
2.3㊣25% |
550 |
450 |
1100 |
60 |
8.0 |
120(P) |
17.5 |
4.0 |
0.6 |
| AMZ13-12P3R7H60 |
3.7㊣25% |
380 |
320 |
750 |
60 |
5.5 |
13.5 |
4.0 |
0.6 |
| AMZ13-10P5R6H60 |
5.6㊣25% |
300 |
250 |
600 |
60 |
4.3 |
11.0 |
4.0 |
0.6 |
| AMZ13-08P9R4H60 |
9.4㊣25% |
180 |
150 |
360 |
60 |
3.0 |
9.0 |
4.0 |
0.6 |
| AMZ13-05P25RH60 |
25㊣25% |
100 |
85 |
200 |
60 |
1.0 |
6.5 |
4.0 |
0.6 |
| AMZ13-03P55RH60 |
55㊣25% |
60 |
50 |
120 |
60 |
0.7 |
4.5 |
4.0 |
0.5 |
| AMZ13-08M4R7H60 |
4.7㊣25% |
180 |
120 |
360 |
60 |
3.0 |
80ㄗMㄘ |
9.0 |
4.0 |
0.6 |
AMWEI PTC Thermistor for Overload Over-current Protection 30V Series
| Part Number |
Resistance
@ 25⊥
R25
ㄗ次ㄘ |
Non-trip
current
IntㄗmAㄘ |
Trip current
@25⊥
It
ㄗmAㄘ |
Max. operating
voltage
Vmax
(V) |
Max. current
Imax
(A) |
Reference
temperature
Tref
(⊥) |
Dimension
ㄗmmㄘ |
| @25⊥ |
@60⊥ |
Dmax |
Tmax |
朴d |
| AMZ14-10R1R8H30 |
1.8㊣25% |
650 |
550 |
1300 |
30 |
4.3 |
140
(R) |
11.0 |
4.0 |
0.6 |
| AMZ14-08R1R8H30 |
1.8㊣25% |
600 |
500 |
1100 |
30 |
3.0 |
9.0 |
4.0 |
0.6 |
| AMZ14-12P1R2H30 |
1.2㊣25% |
750 |
600 |
1500 |
30 |
5.5 |
120(P) |
13.5 |
4.0 |
0.6 |
| AMZ14-12P1R8H30 |
1.8㊣25% |
500 |
430 |
1000 |
30 |
5.5 |
13.5 |
4.0 |
0.6 |
| AMZ14-10P2R7H30 |
2.7㊣25% |
380 |
320 |
700 |
30 |
4.3 |
11.0 |
4.0 |
0.6 |
| AMZ14-08P1R8H30 |
1.8㊣25% |
550 |
450 |
1000 |
30 |
3.0 |
9.0 |
4.0 |
0.6 |
| AMZ14-08P4R2H30 |
4.2㊣25% |
280 |
230 |
560 |
30 |
3.0 |
9.0 |
4.0 |
0.6 |
| AMZ14- 05P10RH30 |
10㊣25% |
170 |
140 |
340 |
30 |
1.0 |
6.5 |
4.0 |
0.6 |
AMWEI PTC Thermistor for Overload Over-current Protection 15V/18V Series
| Part Number |
Resistance
@ 25⊥
R25
ㄗ次ㄘ |
Non-trip
current
IntㄗmAㄘ |
Trip current
@25⊥
It
ㄗmAㄘ |
Max. operating voltage
Vmax
(V) |
Max. current
Imax
(A) |
Reference temperature
Tref
(⊥) |
Dimension
ㄗmmㄘ |
| @25⊥ |
@60⊥ |
Dmax |
Tmax |
朴d |
| AMZ15-10R1R2H15 |
1.2㊣25% |
850 |
700 |
1550 |
15 |
4.3 |
140(R) |
11.0 |
4.0 |
0.6 |
| AMZ15-08R1R0H15 |
1.0㊣25% |
850 |
700 |
1500 |
15 |
3.0 |
9.0 |
4.0 |
0.6 |
| AMZ15-08R1R8H15 |
1.8㊣25% |
600 |
500 |
1100 |
15 |
3.0 |
9.0 |
4.0 |
0.6 |
| AMZ15-07R1R0H15 |
1.0㊣25% |
750 |
600 |
1350 |
15 |
2.5 |
8.0 |
4.0 |
0.6 |
| AMZ15-07R1R2H15 |
1.2㊣25% |
650 |
550 |
1200 |
15 |
2.5 |
8.0 |
4.0 |
0.6 |
| AMZ15-05R4R6H15 |
4.6㊣25% |
350 |
300 |
680 |
15 |
1.0 |
6.5 |
4.0 |
0.6 |
| AMZ15-03R13RH15 |
13㊣25% |
180 |
150 |
350 |
15 |
0.7 |
4.5 |
4.0 |
0.5 |
| AMZ15-10P1R2H18 |
1.2㊣25% |
700 |
600 |
1400 |
18 |
4.3 |
120(P) |
11.0 |
4.0 |
0.6 |
| AMZ15-08P1R0H18 |
1.0㊣25% |
650 |
550 |
1200 |
18 |
3.0 |
9.0 |
4.0 |
0.6 |
| AMZ15-08P1R8H18 |
1.8㊣25% |
550 |
450 |
1000 |
18 |
3.0 |
9.0 |
4.0 |
0.6 |
| AMZ15-05P4R6H18 |
4.6㊣25% |
300 |
250 |
580 |
18 |
1.0 |
6.5 |
4.0 |
0.6 |
| AMZ15-03P13RH18 |
13㊣25% |
145 |
120 |
280 |
18 |
0.7 |
4.5 |
4.0 |
0.5 |
AMWEI PTC Thermistor Current Limiting Devices for Transformer Over-current Overload Protection
(For application of PTC thermistor protector installation inside transformer windings coil)
| Part number |
Resistance
@25⊥
R25
(次) |
Non-trip
current
Int
(mA) |
Trip
current
@25⊥
It
(mA) |
Max. operating
voltage
Vmax
(V) |
Max. current
Imax
(A) |
Reference
temperature
Tref |
Dimension
(mm) |
| @25⊥ |
@80⊥ |
Dmax |
Tmax |
朴d |
| AMZ11-05N121H265 |
120㊣25% |
45 |
25 |
90 |
265 |
0.4 |
100⊥(N) |
6.5 |
5.0 |
0.6 |
| AMZ11-05N151H265 |
150㊣25% |
38 |
20 |
80 |
265 |
0.4 |
6.5 |
5.0 |
0.6 |
| AMZ11-07N22RH265 |
22㊣25% |
110 |
60 |
220 |
265 |
0.7 |
8.0 |
4.5 |
0.6 |
| AMZ11-07N32RH265 |
32㊣25% |
95 |
50 |
190 |
265 |
0.7 |
8.0 |
4.5 |
0.6 |
| AMZ11-07N55RH265 |
55㊣25% |
70 |
40 |
140 |
265 |
0.7 |
8.0 |
5.0 |
0.6 |
| AMZ11-08N30RH265 |
30㊣25% |
100 |
55 |
200 |
265 |
1.0 |
9.0 |
5.0 |
0.6 |
| AMZ11-08N35RH265 |
35㊣25% |
90 |
50 |
180 |
265 |
1.0 |
9.0 |
5.0 |
0.6 |
| AMZ11-08N40RH265 |
40㊣25% |
85 |
45 |
170 |
265 |
1.0 |
9.0 |
5.0 |
0.6 |
| AMZ11-08N39RH265 |
39㊣25% |
95 |
50 |
180 |
265 |
1.2 |
9.5 |
5.0 |
0.6 |
| AMZ11-08N25RH265 |
25㊣25% |
110 |
60 |
220 |
265 |
1.2 |
9.5 |
5.0 |
0.6 |
| AMZ11-10N22RH265 |
22㊣25% |
125 |
70 |
250 |
265 |
1.5 |
11.0 |
5.0 |
0.6 |
| AMZ11-10N18RH265 |
18㊣25% |
145 |
80 |
290 |
265 |
1.5 |
11.0 |
5.0 |
0.6 |
| AMZ11-10N12RH265 |
12㊣25% |
170 |
95 |
340 |
265 |
1.5 |
11.0 |
5.0 |
0.6 |
| AMZ11-12N18RH265 |
18㊣25% |
180 |
100 |
360 |
265 |
2.0 |
13.5 |
5.0 |
0.6 |
| AMZ11-12N12RH265 |
12㊣25% |
210 |
120 |
420 |
265 |
2.0 |
13.5 |
5.0 |
0.6 |
AMWEI PTC Thermistor Current Limiting Devices for Transformer Over-current Overload Protection
(For application of PTC thermistor protector installation outside transformer windings coil)
| Part number |
Resistance
@25C
R25
ㄗ次ㄘ |
Non-trip
current
IntㄗmAㄘ |
Trip current
@25⊥
It
ㄗmAㄘ |
Max. operating
voltage
Vmax
(V) |
Max. current
Imax
(A) |
Reference
temperature
Tref
(⊥) |
Dimension
ㄗmmㄘ |
| @25⊥ |
@60⊥ |
Dmax |
Tmax |
朴d |
| AMZ11-16P6R0H265 |
6.0㊣25% |
390 |
300 |
780 |
265 |
3.1 |
120⊥(P) |
17.5 |
5.0 |
0.6 |
| AMZ11-13P10RH265 |
10㊣25% |
260 |
200 |
520 |
265 |
1.8 |
14.0 |
5.0 |
0.6 |
| AMZ11-12P10RH265 |
10㊣25% |
250 |
200 |
500 |
265 |
1.8 |
13.5 |
5.0 |
0.6 |
| AMZ11-10P15RH265 |
15㊣25% |
180 |
140 |
350 |
265 |
1.2 |
11.0 |
5.0 |
0.6 |
| AMZ11-08P25RH265 |
25㊣25% |
130 |
100 |
250 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08P35RH265 |
35㊣25% |
115 |
90 |
225 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08P45RH265 |
45㊣25% |
105 |
80 |
200 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-08P55RH265 |
55㊣25% |
90 |
70 |
180 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-05P70RH265 |
70㊣25% |
65 |
50 |
130 |
265 |
0.3 |
6.5 |
5.0 |
0.6 |
| AMZ11-03P151H250 |
150㊣25% |
40 |
30 |
75 |
250 |
0.2 |
4.5 |
5.0 |
0.5 |
PTC Thermistor current limiting devices for measuring instrumentation and meter overload and short circuit protection
| Part number |
Resistance
@25⊥
R25
(次) |
Non-trip
current
IntㄗmAㄘ |
Trip current
@25⊥ It
ㄗmAㄘ |
Max. operating
voltage
Vmax
(V) |
Max. current
Imax
(A) |
Reference
temperature
Tref
(⊥) |
Dimension
ㄗmmㄘ |
| @25⊥ |
@60⊥ |
Dmax |
Tmax |
朴d |
| AMZ11-03M151N265 |
150㊣30% |
20 |
15 |
50 |
265 |
0.2 |
80⊥(M) |
4.5 |
5.0 |
0.5 |
| AMZ11-03M102N265 |
1000㊣30% |
10 |
7 |
20 |
265 |
0.1 |
4.5 |
5.0 |
0.5 |
| AMZ11-03M152N265 |
1500㊣30% |
7 |
5 |
15 |
265 |
0.1 |
4.5 |
5.0 |
0.5 |
| AMZ11-04M45RN265 |
45㊣30% |
40 |
30 |
80 |
265 |
0.3 |
5.5 |
5.0 |
0.6 |
| AMZ11-05M601N420 |
600㊣30% |
20 |
16 |
40 |
420 |
0.2 |
6.5 |
5.0 |
0.6 |
| AMZ11-05M232N420 |
2300㊣30% |
8 |
6 |
17 |
420 |
0.1 |
6.5 |
5.0 |
0.6 |
| AMZ11-05M312N420 |
3100㊣30% |
5 |
4 |
13 |
420 |
0.1 |
6.5 |
5.0 |
0.6 |
| AMZ11-07M251N265 |
250㊣30% |
25 |
20 |
50 |
265 |
0.5 |
8.0 |
5.0 |
0.6 |
| AMZ11-07M112M550 |
1100㊣30% |
15 |
10 |
30 |
550 |
0.5 |
8.0 |
7.0 |
0.6 |
| AMZ11-08M12RN265 |
12㊣30% |
120 |
70 |
220 |
265 |
0.8 |
9.0 |
5.0 |
0.6 |
| AMZ11-03N151N265 |
150㊣30% |
30 |
25 |
60 |
265 |
0.2 |
100⊥(N) |
4.5 |
5.0 |
0.5 |
| AMZ11-03N401N265 |
400㊣30% |
25 |
20 |
45 |
265 |
0.2 |
4.5 |
5.0 |
0.5 |
| AMZ11-05N751N420 |
750㊣30% |
25 |
20 |
45 |
420 |
0.2 |
6.5 |
5.0 |
0.6 |
| AMZ11-05P39RN265 |
39㊣30% |
85 |
70 |
170 |
265 |
0.4 |
120⊥(P) |
6.5 |
5.0 |
0.6 |
| AMZ11-05P65RN265 |
65㊣30% |
70 |
60 |
140 |
265 |
0.4 |
6.5 |
5.0 |
0.6 |
| AMZ11-05P601N420 |
600㊣30% |
20 |
16 |
39 |
420 |
0.2 |
6.5 |
5.0 |
0.6 |
| AMZ11-05P122N550 |
1200㊣30% |
15 |
10 |
30 |
550 |
0.1 |
6.5 |
5.0 |
0.6 |
| AMZ11-05P152N550 |
1500㊣30% |
12 |
9 |
24 |
550 |
0.1 |
6.5 |
5.0 |
0.6 |
| AMZ11A-08P70RN420 |
70㊣30% |
64 |
50 |
127 |
420 |
1.4 |
8.5 |
7.0 |
0.6 |
| AMZ11A-08P121N420 |
120㊣30% |
49 |
40 |
97 |
420 |
1.4 |
8.5 |
7.0 |
0.6 |
| AMZ11A-08P151N420 |
150㊣30% |
43 |
35 |
86 |
420 |
1.4 |
8.5 |
7.0 |
0.6 |
| AMZ11A-08P501N550 |
500㊣30% |
24 |
19 |
48 |
550 |
1.0 |
8.5 |
7.0 |
0.6 |
PTC Thermistor Protector Reliability data
| Test |
Standard |
Test conditions |
|忖R25/R25| |
| Switching test at room temperature |
IEC 60738-1 |
Imax Vmax Number of cycles: 50 |
<25% |
| Rapid change of temperature in air |
IEC600628-2-14,
Test Na |
T=TLCT, T=TUCT Number of cycles: 5 T:30min |
<10% |
| Endurance at max. operating temperature and max. operating voltage |
IEC 60738-1 |
Ambient temperature: +60⊥ Maximum Operating Voltage Current limited to Imax. Time: 24 hours |
<25% |
| Storage in damp heat |
IEC 600628-2-3 |
Temperature of air: 40⊥ Relative humidity of air: 93% Duration: 56 days |
<10% |
| Lead wire tensile |
GB2423.29 |
Test Ua: pull strength 10N, for 10 seconds Test Ub: bending 90∼, pull strength 5N, for successively twice. Test Uc: revolving 180∼, successively twice. |
≒20% |
Reference information in selecting PTC thermistor over-current protection devices for overcurrent and overload protection.
1) Maximum operating voltage
PTC Thermistor over-current protection device is connected in series in the circuit , In normal
operating state, only a small portion voltage is on PTC thermistor protector. When PTC
thermistor current limiting devices is in high resistance state, it must bear almost all the power
voltage. Therefore in PTC thermistor protector model selection, it must have sufficient
high operating voltage, and also power voltage fluctuation must be taken into
consideration.
2) Rated current ( Non-trip current) and Switching current (Trip
current)
The PTC thermistor over-current protection device should have sufficient high rated current (that current at
which the PTC thermistor protector will under no circumstances turn off) within the suitable
voltage class. Consider whether the overall layout of the circuit can handle the
increased power for the short time until the PTC thermistor protector reduces it. Here a
worst case estimate is necessary. Rated current ( Non-trip current) and
Switching current (Trip current) depend on the ambient temperature. So, as the
worst case for the rated current, the maximum permissible temperature for the
application should be taken, and for the switching current the lowest possible
ambient temperature. In order to get reliable switching function, tripping
current should be at least twice of non-trip current.
3) Maximum current permissible in maximum operating voltage
When PTC Thermistor over-current protection device is required for protective function, it needs to check
whether there is the case that the maximum permissible current, which has been
listed in data sheet, has been exceeded. Overloading the PTC thermistor protector by too
high a switching current must be avoided, it may lead to PTC thermistor protector destroyed, or early failure.
4)Selection of Reference temperature (also called Switch temperature or Curie
temperature)
We can offer PTC thermistor for over-current protection with reference
temperature 80 ⊥, 100 ⊥, 120 ⊥, 140 ⊥. The rated current (non-trip current)
depends on reference temperature and ceramic body diameter. In consideration of
cutting down cost, high reference temperature and small dimension PTC Thermistor current limiting devices shall be more economical, but it may leads to higher PTC thermistor surface temperature, and need to
check whether it will cause undesired unfavorable effects. Generally, reference
temperature should be 20- -40 ⊥ higher than maximum operating ambient
temperature.
5) Application environmental effects
If there is any contact with chemicals or use of potting or
sealing compounds, all due care should be taken. The reduction of the titanate
ceramic that can be caused by chemical effects on the surface of the thermistor
and the resulting formation of low-resistance conducting paths. And the altered
thermal relations in the sealant can lead to local overheating of the PTC
thermistor protector and thus to failure.
An example of PTC thermistor over-current protection devices part selection for overload protection
of power transformer.
An transformer has primary voltage 220V, secondary voltage 16V,
secondary current 1.5A , primary current 330mA in abnormal condition, it shall
enter into protective state within 10 minutes. Operating ambient temperature:
-10- -40 ⊥ , temperature may rise 15- -20 ⊥ in normal operating state. PTC Thermistor will be installed near transformer. Please select an appropriate PTC thermistor part for primary protection.
1) Determine maximum operating voltage
Operating voltage 220V, considering power fluctuation, maximum operating
voltage should be
220V x (1+20% ㄘ =264V
Maximum operating voltage shall be 265V.
2) Determine non-trip current
According to calculation and actual measurement, primary current is 125mA in
transformer normal operation. In consideration the ambient temperature in
installation position may reach to 60 ⊥ , Non-trip current in 60 ⊥ should be
130--140mA.
3) Determine trip current
As the ambient temperature in PTC thermistor protector installation position may reach -10 ⊥ , non trip current in -10 ⊥ should be 320-330mA, tripping time within 5 minutes.
4) Determine rated zero power resistance at 25 centigrade. R25
PTC thermistor is in series in the primary circuit, the voltage decreasing
should be possibly small, the heating power of PTC Thermistor itself also
maintain possibly small. Generally, the voltage decreasing should be less than
total power voltage 1%. We can get R25 through calculation
220V X 1% ‾125mA=17.6 次
5) Determine maximum current
Trough practical measurement, primary current can reach 500mA in transformer
secondary circuit in short circuit state. If considering that larger current may
pass through PTC thermistor in the state of primary coil partial short circuit.
The maximum current should be more than 1A .
6) Determine reference temperature and dimension of PTC thermistor over-current protection device
Maximum ambient temperature in PTC thermistor protector installation position may reach 60 ⊥ , reference temperature should be 40 ⊥ higher than that, then the reference temperature can be 100 ⊥ . In considering cutting down cost, also PTC thermistor is not installed in the transformer windings coil, higher surface temperature won't have unfavorable effect to transformer, therefore reference temperature can also be 120 ⊥ , and then the diameter of PTC Thermistor can be smaller.
7) Determine PTC thermistor over-current protection device part number.
Based on the above technical requirement, in reference of our technical data, AMZ11-10P15RH265 shall be more appropriate.
Maximum operating voltage 265V, rated zero power resistance at 25C (R25) 15 次㊣20% , non-trip current 140mA , trip current 350 mA , maximum current 1.5A , reference temperature 120 ⊥ , diameter 11mm .
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