NTC 80-20

[2PAC Mafia]

Hi guys,

I have a treadmill board with NTC damaged connected at 220Vac line. I only could see NTC 80-20 so I´m not sure which is the replacement value.

May be I can replace by a fuse as the NTC is the only protection it has on the AC line, but which would be the replacement fuse value if the output is for a motor 180Vdc regulated by PWM (mosfet is IRFP360 and motor protection peak diode is U15A60)

 

[KeepItSimpleStupid]

The number seems familiar. Search ETO.

 

[alec_t]

connected at 220Vac line

Is it connected in series with the line? Sounds like an inrush current limiter.

 

[Les Jones]

Could the marking be "NTC 8D-20" ?
If so here is one source.
**broken link removed**

Les.

 

[2PAC Mafia]

Hi,

Is it connected in series with the line? Sounds like an inrush current limiter.

Yes

Could the marking be "NTC 8D-20" ?
If so here is one source.
**broken link removed**

Les.

I think you are right, it should be this one as the body was damaged I can´t be 100% sure if it was a 0 or a D.

In any case I already replaced it by a 12A fuse. Thanks.

 

[Les Jones]

A fuse does not provide the same type of protection. When power is first applied the NTC thermistor has a high resistance so the current is limited. As there is power being dissipated in the thermistor it heats up. As a result of it heating its resistance decreases. at some point an equilibrium is reached when the power dissipated in the thermistor is just enough to maintain the temperature. This works well in limiting the switch on surge when charging large capacitors. It does not provide protection against a fault.

 

[KeepItSimpleStupid]

here https://www.electro-tech-online.com/threads/technics-sb-as500-repair.144812/ is a discussion that may be worthwhile to look at.