Troubleshooting mazak qt10 spindle controller alarm

[CrashGordon1]

Hey guys, I recently bought a mazak qt10 with a t2 control with a Mitsubishi FREQROL FR-SE spindle controller and have had an issue keeping me from getting it up and running. I inspected the machine at the shop of the previous owner as it was under power and at the time was in production. Everything was working fine and it was making good, repeatable parts. I bought it and had it delivered to my shop, had an electrician install and wire an rpc from American rotary and powered up the machine. I put a piece of stock in the chuck and ran the same program as I had seen run in the previous shop. As the program began all was fine until it made a facing cut, retracted to take another cut, then stopped above the part, the spindle coasted to a stop and I got the alarms: 20 NMI e-stop and 204 spindle controller malfunction. I would later get the same 2 alarms if I was jogging the spindle at high rpms and push spindle stop or even decrease spindle speed button, also coasting to a stop. I went into the program and slowed down max rpm from 3,000 to 1500, 800 then 300. Every time I ran it slower it would get farther in the program and at 300 rpm it finished the program while cutting air. Although no alarms came up this time, this is way too slow to effectively turn a part. The only thing I'm doing different than the previous owner is he was running the machine at 208v 3phase and I'm running 240v with rpc. I was told maybe a step down transformer would fix the issue as it's probably meant for 200v (Japanese standard). Does this sound like over voltage may be my issue? Considering I'm getting the alarms at high rpms near and during spindle braking sequences? I still intend to install a step down transformer but can anyone shed some more light on the issue? Thanks!

 

[cnctoolcat]

Yes, your problem could be high voltage.

Your QT10 with T2 control should have a main multi-tap transformer. You can set the taps for 240V input, then the transformer feeds the machine the required 200V. Check this.

The FR-SE spindle drives are fragile as they age, and are probably the most common failure point for any T1/T2 Mazak QT's.

You have to open the rear electrical cabinet doors and see what alarm(s) the FR-SE is showing (a series of LED lights...)

There is some good info on the web on how to diagnose and repair FR-SE spindle drives, or retrofit if necessary.

Good luck with it,

ToolCat

 

[CrashGordon1]

Yes, your problem could be high voltage.

Your QT10 with T2 control should have a main multi-tap transformer. You can set the taps for 240V input, then the transformer feeds the machine the required 200V. Check this.

The FR-SE spindle drives are fragile as they age, and are probably the most common failure point for any T1/T2 Mazak QT's.

You have to open the rear electrical cabinet doors and see what alarm(s) the FR-SE is showing (a series of LED lights...)

There is some good info on the web on how to diagnose and repair FR-SE spindle drives, or retrofit if necessary.

Good luck with it,

ToolCat

The FR-SE showed LEDs on 12,14 and 15 so it looks like it's certainly over voltage, where are the transformer taps located in the machine?

 

[Scruffy887]

Usually (but not always) the transformer is in a separate metal enclosure with vents. It may even have a leg to the floor for support. Easy enough to trace the wires back from the electrical cabinet, should be very close by. Remove the cover and you will see the taps.
My new VTC 200 has the transformer on top of the electrical cabinet for some strange reason. Odd place to put a heavy chunk of iron and copper.

 

[CrashGordon1]

Usually (but not always) the transformer is in a separate metal enclosure with vents. It may even have a leg to the floor for support. Easy enough to trace the wires back from the electrical cabinet, should be very close by. Remove the cover and you will see the taps.
My new VTC 200 has the transformer on top of the electrical cabinet for some strange reason. Odd place to put a heavy chunk of iron and copper.

Thanks for the advice guys! The spindle control alarm is now fixed after switching the voltage taps and it brakes properly. Now the problem is when I try to run the program, the spindle ramp up is really fast and is shutting off power to the machine. Attempt 1. I set the max rpms to 2500. Attempt 2. 1500 rpms. Same outcome for both. Does this sound like a parameter needs to be changed to slow down the spindle ramp up? Note: I wasn't having ramp up issues when running over voltage but rather braking problems.

 

[cnctoolcat]

Thanks for the advice guys! The spindle control alarm is now fixed after switching the voltage taps and it brakes properly. Now the problem is when I try to run the program, the spindle ramp up is really fast and is shutting off power to the machine. Attempt 1. I set the max rpms to 2500. Attempt 2. 1500 rpms. Same outcome for both. Does this sound like a parameter needs to be changed to slow down the spindle ramp up? Note: I wasn't having ramp up issues when running over voltage but rather braking problems.

For the FR-SE, you set Dip switches on the spindle drive itself to adjust the acceleration and deceleration rates.

I don't have the manual on this computer, but look for a FR-SE Maintenance Manual...it describes the Dip switch settings.

And yes, I recommend slowing the accel/decel rates on the older FR-SE and FR-SF spindle drives. Much easier on the drive--extends it's life and reliability, it saves electricity, and you add very little cycle time.

ToolCat

 

[CrashGordon1]

For the FR-SE, you set Dip switches on the spindle drive itself to adjust the acceleration and deceleration rates.

I don't have the manual on this computer, but look for a FR-SE Maintenance Manual...it describes the Dip switch settings.

And yes, I recommend slowing the accel/decel rates on the older FR-SE and FR-SF spindle drives. Much easier on the drive--extends it's life and reliability, it saves electricity, and you add very little cycle time.

ToolCat

Thanks toolcat, just found an old thread on dip switches for the FR-SE and gave it a try, now my machine is up and running and currently making chips, I really appreciate the help!