A real bad day

[mactec54]

Than you all. I pulled the cover on the spindle motor and it is 7.5 hp. I took pictures of the new VFD drive. It is the copy of the old one. That has me scared of the 7.5hp. If I may ask what is RDC and breaking resistor and where are they at. Rest assured I will have an Milltronics tech install after I get all the parts. I did pull all the XYZ drive boards and they look fried. I am also sending a picture of the 240 volt long tube, that is also fried. Just a toolmaker not electronic tech.

That new VFD Drive is not the same as the one that was in there 230v, did the VFD fail before and someone replaced it with the wrong one, the 40P2 is a 460v Drive

Do you have 460v 3 Phase supply

[mactec54]

RPC = rotary phase converter

Braking resistor = that big gray thing in the first picture ( the long gray tube). I'll try to give a simple explanation of its purpose without getting too technical. This will not be exactly technically correct and only applies to electric motors connected to VFDs and similar drives. When the motor is told to stop, it becomes a generator and the power needs to go some where, so rather than feeding the power back into the VFD, the VFD shunts off that excess power to the braking resistor which in turn converts the excess power into heat. Very much like the brakes in your car work, they convert the momentum of your car into heat.

That CIMR-PCU40P2 VFD is a 460V, 1/2 HP rated. It will not work for your spindle motor. If your motor is rated at 7.5 HP then you need a VFD rated at 7.5HP, and in this case you need 230V (200 - 240) input, not 460V (380 -460)

If you need help choosing a VFD, we'll be happy to help. And Mactec54 and I will argue about it But my favorite vendor is Automation Direct. https://www.automationdirect.com/adc...rpose/gs3-27p5

It will depend on what his machine needs, the this old Yaskawa drive, which is designed for CNC machines, spindle orientation Etc. there is nothing to argue about. if he does not need any of those things to do with tool change, then any quality VFD Drive will work. 230V 10Hp

[sportybob]

HI All I don't get to CNC Zone as often as I used to.
The IGBT in the drive fails and just dumps incoming voltage to the breaking resistor.
I can make the drive cables, and get you a good drive replacement.
Give me a call.
I am here to help

Sportybob
952-288-6340

[Grasshopper75]

Bob thank you Mikes Mold & polishing I will have Dave Miller come out and look at this, before going on. The power company checked the line on and before/ after Oct 13th. There were no spikes. The machine is on a 3ph converter.

[pmhupman]

Hope this is not too much technical info, but here it goes...

I've had this happen three times in my Saftronics VFD that I got in my used Partner 1F. This VFD has an "IGBT" module that contains four sets of transistors as well as three power rectifiers. In normal operation, each of the three phases of power comes into the VFD through a rectifier, and turns into pulsed, high voltage DC and a bank of capacitors smooths out the pulses. This high voltage DC is sent to the three banks of transistors and switched by the VFD controller to create the speed-controlled phases that run the spindle motor. When the control gets a stop command, it turns off the three sets of transistors, waits a fraction of a second, then turns on the final transistor into the braking resistor to short the motor winding, causing the motor to brake. All VFDs work in this basic manner although some have separate IGBTs and more or less features on the control section.

In the case where the Safetronics failed, one of the three banks of transistors shorted to the high voltage power and when the VFD got a stop command, the input power (whether single phase or three phase) was shorted through the rectifiers and directly to the braking resistor (which makes a lot of smoke, and fries wires if you don't catch it soon enough).

I think there was originally a failure caused by an overvoltage since there was an "MOV" in the unit "which is an overvoltage protection device" blown up in the VFD when I repaired it. It had been repaired before, evidenced by some of the capacitors not matching. After my failure, I replaced the MOV and IGBT module and I was off ot the races. The VFD functioned normally for a while, then failed again. I replaced the module again, and it ran for a while and failed again. I wanted to repair it again, but found the board was too damaged to repair.

In the end, I suspect when the VFD was originally repaired (by the previous owner of the mill), following replacement of exploded capacitors, the board was not properly cleaned, causing leakage paths on the controller board. The leakage paths caused timing issues and the IGBT to not shut off before the braking was turned on, causing the phase and braking transistor to short and therefore failing the VFD. Every failure had the same symptoms.

I've seen this reported a few times and I'd have to guess that most of these VFDs have had previous repairs and may have had this leakage. This is all speculation of course, but I do electronics failure analysis for a living, so it's at least an educated guess.