Hi,

I have an IFT drive for treadmill like the one attached in the picture. The problem is that, for some reason, an igbt is getting shorted after the motor starts. I attach a circuit fragment where the igbt is located. The drive has a module SKiiP 13NAB065V1 [datasheet: https://www.alliedelec.com/m/d/4d48f52f52ac0a6302832c95f76b2e94.pdf].

The igbt is located at the input, that's why I find it difficult to understand what's happening.It's previous to the charge circuit of the DC Bus. Look at the circuit. The module has the rectifier and igbt all integrated.

What could be happening?

 

If it is a typical T.M. motor fitted with a flywheel, it could possibly be that the slow/zero start interlock function is not operating.
Max.

 

If it is a typical T.M. motor fitted with a flywheel, it could possibly be that the slow/zero start interlock function is not operating.
Max.

What's the main purpose of that transistor?

 

Most T.M. operate with some kind of safety that if one is standing on the deck when turning the T.M. on, you cannot go into high speed if it was set at that when turned off.
This is usually the cruder type such as the MC-60 etc, where if it where not for the safety feature, this would occur.
It can be defeated on the MC-60 just by lifting a resistor.
Max.

 

That transistor keeps getting shorted when high load on treadmill. I thought it was a chopper circuit, but the thing is that the SKiiP 13NAB065V1 has another chopper circuit inside. So, two chopper circuits?

That IGBT is located at the input, so it also blows the rectifier. I really don't get the purpose of this transistor. Any suggestion or help?

 

I have no schematic info on that model.
Max.

 

The transistor and the inductor are used as buck-booster, from 110V AC going through the module rectifier as 155V DC, they load the capacitors with 310V DC. So when the transistor is open energy is loading the inductor, when is closed the energy is loading the capacitors. Works with width modulation depending of the motor load. So if you have a bigger load on the motor you need to change the walking belt.

 

I have the 13NAB065V1 keeps blowing like the picture, still didn't know why, and i changed the treadmill itself and it also got blown, I'm starting to think it's a Chinese part (not original) that is faulty. also found some 82 ohm and zener diodes blown after fixing them they get blown also with the 13NAB065V1

 

I can think of the capacitors as well as the ESR of both (2 of 680uf 400v) together is around1.6 ohm