Has anyone here ever replaced the resistors in a Yaskawa drive?

rb07565 · Dec 3, 2014

I'm fairly certain the braking resistors are burnt out on my 1999 Hurco VMC. I get a spindle load alarm fault anytime the the spindle brakes for a tool change from speeds above 2800 to 3000. If you manually reduce RPM slowly the spindle load increases but does not fault. Anyhow, we've changed resistors on Allen Bradley drives before and it isn't all that difficult, where are they located in the Yaskawa? I was wondering if anyone could give me some advice or photos. I can't tear the machine apart and leave it sit while I explore the drive and order parts. It HAS to run, even crippled. The drive is a Yaskawa Varispeed 626VM3, Model# CIMR-VMW27P5

legendboy · Dec 3, 2014

Do you know the exact error code it shows?

Guest · Dec 3, 2014

I have the exact same spindle drive on a Kitamura that is down for a bad power supply. Pretty sure you have the same set-up. What does the alarm say exactly? If you have the same set-up there will be a braking unit in the system that bleeds off the DC bus spikes, that unit is external to the spindle drive. My braking resistors are connected to the braking unit but remotely located under a cover on the side of the machine. They are bigger than road flares and can be easily checked with a meter. Those rarely go bad, it could be the braking unit itself. Most of them have a light that comes on when they are working, mine failed years ago and had to be replaced.
Wish I could help you with photos, but on crutches and pretty immobile for a few more days.

rb07565 · Dec 3, 2014

I'm not in the shop right now but I believe it's F400 Inverter over voltage fault

rb07565 · Dec 3, 2014

Dualkit said:
I have the exact same spindle drive on a Kitamura that is down for a bad power supply. Pretty sure you have the same set-up. What does the alarm say exactly? If you have the same set-up there will be a braking unit in the system that bleeds off the DC bus spikes, that unit is external to the spindle drive. My braking resistors are connected to the braking unit but remotely located under a cover on the side of the machine. They are bigger than road flares and can be easily checked with a meter. Those rarely go bad, it could be the braking unit itself. Most of them have a light that comes on when they are working, mine failed years ago and had to be replaced.
Wish I could help you with photos, but on crutches and pretty immobile for a few more days.

I looked for an external set-up but I didn't see one. That doesn't mean there isn't one however, I very well could have overlooked it.

MLeonard · Dec 3, 2014

Does the drive have main terminals marked "B1/P" and "B2" (or something like that), probably in between the incoming power (R, S, T) and outgoing motor (U, V, W) terminals? If so, do the "B" terminals have wires on them? If so, follow those wires and you will find your braking unit or braking resistor.

rb07565 · Dec 3, 2014

I will look again this afternoon. I haven't had this machine very long and it has done it since we got it. I do allot of stainless so I've just been using it as is while I researched it. I however got a new customer who has allot of Aluminum and mild steel and it's become urgent. I am wondering if it was even possible that these drives came with internal resistors? Were there external ones that were removed? I don't know. What I really need is drive schematic for that model drive. I bought the machine from a used eq. dealer so they will be no help.

Another question...I have a 15hp Allen Bradley PowerFlex 755 drive that I bought a couple years ago for a project that never materialized. Has anyone hear ever subbed out a Yaskawa spindle drive for a different brand. I was wondering if it's even possible.

Guest · Dec 3, 2014

Sorry that I can't hobble to the shop and check but I believe MLeonard is correct about those wire markings, it rings a bell. If the problem only occurs when decelerating the spindle your culprit is not the spindle drive. I had the exact same same happen to me with the exact same drive. The spindle drive is connected to the braking unit that is probably 1/2 the size of a shoe box, it could be outside the main cabinet under a cover. While the braking unit has some resistors and a heat sink inside it is connected to a large resistor rack that can be anywhere away from the braking unit itself. Those resistors are usually inside a side pocket with a grated cover over them as they can get rather hot. My guess is the braking unit has failed and it isn't engaging the resistor rack when it should.

If you don't have a manual on the Varispeed they are available from Yaskawa for free download. There is a lot of diagnostics that you can view, you will be able to quickly figure out where the over voltage is. I am pretty sure your Varispeed is fine which is good because they are expensive, something it is connected to is causing the problem, my vote goes for the braking unit.

rb07565 · Dec 5, 2014

I looked over the machine up and down and can't find an external braking resistor nor any specific terminals on the drive. I'm beginning to believe that they are internal to the drive. If they are does anyone know where they are located and or what they look like?

legendboy · Dec 5, 2014

Can you post a pic of the drive terminals?

rb07565 · Dec 5, 2014

Here's a few pics I took last night. Any help is appreciated

cnctoolcat · Dec 5, 2014

One or more of the main power transistors could be failing as well. These are located under the main circuit board, looks like there is 6 of them. They not only "create" the power to go out to the spindle motor, but they manage the power coming back in when the motor is decelerating.

You can find them on ebay, as well as several Yaskawa spindle drives as well.

Good luck with it.

ToolCat

Guest · Dec 5, 2014

rb07565 said:
Here's a few pics I took last night. Any help is appreciated

I thought your Varispeed number looks familiar, but maybe mine is different, I am still too gimpy to go out and look. Yaskawa had something called a descriptive manual for a 626vm3 on their website for the F-400 alarm that trouble shooting guide gave basically only two things outside of wrong settings and your settings have to be fine.

Main contactor failure which basically would be bad contacts or coil problems causing improper voltage across the phases, not likely or get this "controller failure." To me along with your wiring set-up the braking system is self contained like you thought. Their are a few other manuals on a 626vm3 with an extra letter in it on the Yaskawa website, check them out they might fit yours. If I were you I would take the top board off and just look underneath at the next board, you might find something obvious.

rb07565 · Dec 5, 2014

Another check that slipped through the cracks. I'm running this thing on a roto-phase so I'm going to check the incoming voltage. According to Yaskawa if the incoming voltage is way too high or too low it can cause the drive to throw an F400 error during deceleration. Anyone run into this? If so what's the tolerance for incoming voltage phase to phase?

rb07565 · Dec 5, 2014

Dualkit said:
I thought your Varispeed number looks familiar, but maybe mine is different, I am still too gimpy to go out and look. Yaskawa had something called a descriptive manual for a 626vm3 on their website for the F-400 alarm that trouble shooting guide gave basically only two things outside of wrong settings and your settings have to be fine.

Main contactor failure which basically would be bad contacts or coil problems causing improper voltage across the phases, not likely or get this "controller failure." To me along with your wiring set-up the braking system is self contained like you thought. Their are a few other manuals on a 626vm3 with an extra letter in it on the Yaskawa website, check them out they might fit yours. If I were you I would take the top board off and just look underneath at the next board, you might find something obvious.

I was typing the most recent reply at the same time you were. I'm going to check the incoming voltage this afternoon with a meter that will track spikes.

MLeonard · Dec 5, 2014

The terminals I quoted for external brake connection were for a 626-VM3C (found on Bridgeport Torq-Cut machines). I see now that yours is different.

Look on www.yaskawa.com for manual SIE-S626-6C.

Page 36 of that manual says "Braking Method: Regenerative brake with power regenerative function".

I think that may mean that it regenerates to the AC service lines instead of dumping power to resistors. If so, that may not play well with a rotary phase converter.

Guest · Dec 5, 2014

rb07565 said:
I was typing the most recent reply at the same time you were. I'm going to check the incoming voltage this afternoon with a meter that will track spikes.

When mine was running off a rotary also I was in the low 230's which was on the high side. The only thing I remember having an incoming setting was the braking unit. I think my Varispeed is probably that C model that Mleonard was mentioning that is why the number looked familiar. Read the manual, mine actually has a way to have the different voltages displayed on the digital read out, that is how I determined the braking unit wasn't working.

There could be voltages internal to the Varispeed that would be hard to meter. Maybe there is also a setting if you have incoming voltages on the high side. Also your rotary's output is going to vary with load. It will be higher when it isn't connected to a running machine.

legendboy · Dec 5, 2014

MLeonard said:
The terminals I quoted for external brake connection were for a 626-VM3C (found on Bridgeport Torq-Cut machines). I see now that yours is different.

Look on www.yaskawa.com for manual SIE-S626-6C.

Page 36 of that manual says "Braking Method: Regenerative brake with power regenerative function".

I think that may mean that it regenerates to the AC service lines instead of dumping power to resistors. If so, that may not play well with a rotary phase converter.

the OP needs to tell us if this is new behaviour or if this is a new to him machine

rb07565 · Dec 5, 2014

legendboy said:
the OP needs to tell us if this is new behaviour or if this is a new to him machine

It's done it since I got it. I haven't had this one that long. See post #7

rb07565 · Dec 8, 2014

UPDATE... It turns out it wasn't the resistors or the drive at all. I measured the voltage coming from the rotary phase converter and L3 to L2 was measuring almost 270!! WAY HIGH. I unhooked some of the capacitors until the voltage measured a normal level across all legs. I haven't had any spindle faults so far. I will keep the thread updated if there are anymore problems. Thanks for the help

Has anyone here ever replaced the resistors in a Yaskawa drive?

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