IGBT fault

[Cahya]

I have a Toyodenki VSD tipe VF61 for 22 kW motor.

I used it with DC reactor. And this VSD is used to drive a plastic machine.

My problem is: when I turn this machine without any load, it can work very smooth and normally.

but when I place the 1/4 of the load, the motor seem like there is any braking or one of the phase is loss.

And there is any alarm fault said about "over voltage".

I try this VSD to a lighter motor and this VSD is work normally.

After I tried it again in 22 kW motor it worked not stable. After all there is an alram about IGBT fault.

I have checked this IGBT and one of them is fault (short circuit).

This IGBT type is PM200DVA120 manufactured by Mitsubishi.

And now I want to buy this IGBT but i'm afraid that there will be any fault again in other IGBT or maybe the new one.

Anyone can give me advice where I must checked this problem?

Especially inside the inverter, maybe in optocoupler or in the power supply setting or else.

The motor seem ok , cause now I drive it with another VSD and work very well.

Or maybe anyone have this VSD manual book can give me some copy or info where I can have this manual book.

thank you

[mariomaggi]

Dear Cahya,

please give some info regarding the type of load: friction load, low- or high-inertia load, or "extruder" "mixer" etc.

 

If the load is inertial, please specify if there is an electronic brake unit connected to the DC bus of your inverter.

 

Regards

Mario

[Carl]

If it is not a smart IGBT then you should also check out the driver circuit. The other IGBT life span is reduced if they go beyond their specified ratings. When I used to repair Inverters I replaced the driver circuit and all the IGBT this insured that I had done everything that was reasonably practical. Make sure your snubber network is OK

 

If voltage regeneration is an issue: a simply fix increase the deceleration else put in a braking circuit