EEVblog Electronics Community Forum

Electronics => Repair => Topic started by: XaviPacheco on September 27, 2018, 02:19:10 am

Title: Replacing faulty thermistors
Post by: XaviPacheco on September 27, 2018, 02:19:10 am
I have a three phase motor controller which has two thermistors SL22 1R020, located at the positive and negative leg of a bridge rectifier respectively. Then, it feeds a bank of capacitors. I can try uploading an schematic if needed for this. One of the thermistors is burnt. I don't have the same replacement. However, I have this one SL32 2R025. Do you think it works? I haven't made a deep analysis on why the designer selected that thermistor value.
Title: Re: Replacing faulty thermistors
Post by: coromonadalix on September 27, 2018, 09:46:52 am
the first :      SL22 1R020  is 1 ohms at 20 amps
the second : SL32 2R025  is 2 ohms at 25 amps

If the thermistor has blown, it must have or had a reason  ?   Sure you can do an substitution with the second part number.

But maybe the motor may have begun to show problems symptoms ??? Do they need some maintenance ?? bearing check, rotor check, lubrification check, dust clean up ??

We had failed bearings in one of our at my job, it began to trigger current protection ??