Looking for information on my VM-17

[SEK22Hornet]

I just bought a VM-17 Partner 1 built in 1996. Long story made short, the Z axis was giving errors and the owner brought in a tech to work on it about 4 years ago. Was told the Centruion 5 control was bad so he sent it in for repair - was sent a Centurion 6 which he installed. Still had the drive error showing up. Ran it a little bit and had another tech come in to look at it. Was told he needed to have the servo motor rebuilt so he sent it to be rebuilt. This has the brushless DC servos. Came back, tried to install the motor and could not get it run. At that point they tore the motor apart and and it has been sitting ever since. The tech said it had the wrong voltage encoder in the motor (said it should be a 7 volt and was a 5 volt). Well, the encoder is marked 5-28 volts (by the way - I worked in electronics as a tech and in Engineering for over 30 years so I'm comfortable troubleshooting this thing) so i'm pretty sure the encoder is not a problem voltage wise. I still need to get the machine powered up but I also need to get the motor put back together before I can wire it up and start trouble shooting. Thinking about picking up a brushless servo amp to help me bench check the motor before wiring it back into the machine. Don't have much wiring info - just a few pages that he had. Milltronics wants $150 for the manual. Hoping I could come up with the motor wiring without spending that if I can. My first guess is that the original problem is more likely the Servo Dymanics amplifier (bad caps due to the age maybe?) Need to see if anything else needs attention due to it being moved in one piece also (controller, crt, etc.) Also looking for a few key tops - wonder if they are still available? a few are missing. I have been told that this machine should run on single phase - it has a saftronics VFD. Anyone now if this is correct? It was always ran on 3 phase per the original owner. Spindle is a two speed (changed with a manual belt change) -

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[bmoore]

I just bought a VM-17 Partner 1 built in 1996. Long story made short, the Z axis was giving errors and the owner brought in a tech to work on it about 4 years ago. Was told the Centruion 5 control was bad so he sent it in for repair - was sent a Centurion 6 which he installed. Still had the drive error showing up. Ran it a little bit and had another tech come in to look at it. Was told he needed to have the servo motor rebuilt so he sent it to be rebuilt. This has the brushless DC servos. Came back, tried to install the motor and could not get it run. At that point they tore the motor apart and and it has been sitting ever since. The tech said it had the wrong voltage encoder in the motor (said it should be a 7 volt and was a 5 volt). Well, the encoder is marked 5-28 volts (by the way - I worked in electronics as a tech and in Engineering for over 30 years so I'm comfortable troubleshooting this thing) so i'm pretty sure the encoder is not a problem voltage wise. I still need to get the machine powered up but I also need to get the motor put back together before I can wire it up and start trouble shooting. Thinking about picking up a brushless servo amp to help me bench check the motor before wiring it back into the machine. Don't have much wiring info - just a few pages that he had. Milltronics wants $150 for the manual. Hoping I could come up with the motor wiring without spending that if I can. My first guess is that the original problem is more likely the Servo Dymanics amplifier (bad caps due to the age maybe?) Need to see if anything else needs attention due to it being moved in one piece also (controller, crt, etc.) Also looking for a few key tops - wonder if they are still available? a few are missing. I have been told that this machine should run on single phase - it has a saftronics VFD. Anyone now if this is correct? It was always ran on 3 phase per the original owner. Spindle is a two speed (changed with a manual belt change) -

This is cent 5 with glentek ga370-3 drives. Don't know if it's for brushless motors or not.

Sent from my SM-G935V using Tapatalk

[rl49]

See Attached E-Partner 1-6-7 12-15HP ATC AC VMCent5 1995.pdf page 4 is brushless dc with a C5 Schematic, don't know how the C6 control will affect it.

Ron

[SEK22Hornet]

Thanks - I found that one on line it is for the brush type servo motors. Lacks the commutator feedback for the brushless motor - not sure if wire colors match up or not on the rest.

[SEK22Hornet]

Thanks - I found that one on line it is for the brush type servo motors. Lacks the commutator feedback for the brushless motor - not sure if wire colors match up or not on the rest.

I forgot to note that this response was directed at bmoore - thanks again!

[SEK22Hornet]

See Attached E-Partner 1-6-7 12-15HP ATC AC VMCent5 1995.pdf page 4 is brushless dc with a C5 Schematic, don't know how the C6 control will affect it. Ron

Thanks Ron - this looks like it will help me out. I think the manufacturer of the motor may be different than mine but it should get me a little closer.

[SEK22Hornet]

See Attached E-Partner 1-6-7 12-15HP ATC AC VMCent5 1995.pdf page 4 is brushless dc with a C5 Schematic, don't know how the C6 control will affect it.

Ron

As far as the difference between the C5 and C6, he said the upgraded control pc was a plug in replacement, so the wiring ought to be pretty close to what I have in that respect - I do know my spindle is different than the one in this manual.

[Jim27]

How far apart did the take the motor? Rotor out of stator? The motor should be fairly easy to test but if they removed the encoder and there is no alignment keying the encoder has to be aligned to the motor. It's doable with another motor to spin the motor assembly and a oscilloscope to look at timing. You can likely use the existing amps for testing.

For the keycaps you probably have to find an old unit that it being parted out (I have been told there is one on line but I don't know the site it is on) or you could try 3d printing the caps. You would have to create the model from an existing cap.

[SEK22Hornet]

They took the end cap off and took out the encoder, tach, and connector board. The motor has a brake so the rotor and stator are still together and locked in position - that may be the only thing that lets me get it back to together in correct time. I'll look at it closer to see if there is and timing mark on anything. I do have a dual trace scope so if I can find out what the timing needs to be I can probably rig up something to get it timed if I need to.

[Jim27]

The rotor still being assembled and locked to the stator saves you from trying to clean little bits of metal off the rotor magnets which is a pain. But it sounds like you still have encoder alignment to do. Post a picture of the motor shaft where the encoder goes and the encoder assembly. If it's like most I have seen the motor shaft has an extension the the encoder wheel slips over and locks onto which is unkeyed. There is also often a special tool or spacer to get the wheel at the proper location axially. You may be able to eyeball this from the other motors or get the details from the encoder manufacturers web site.

[sportybob]

Hi "hornet" It sounds like you have Servo Dynamics AC drives ( SDBF-1422) with CSM AC motors.

PM me, with your contact info or call me 952-288-6340

sportybob

[SEK22Hornet]

Here are some pics of the motor and related items on my mill. I'm gathering up hardware to put it back together to see if I can make it run. Thnk I'll make up a short test harness to start with so I can directly connect to the driver board for testing.

[Jim27]

Is that a shaft key I see on the right side of the shaft in picture 4? If so it may be that the encoder is aligned with that key. The screw holes in the encoder bracket are often slots so that the encoder body can be turned and the timing adjusted but the slots on the encoder bracket are such to not allow any turning (or very little). It appears you may not need to worry about tuning the position of the encoder. Is there some way to clamp the internal section of the encoder to the shaft or is it just a very tight slip fit? Usually there is some way to clamp the rotating part of the encoder to the shaft.

For the motor test you can spin the motor with a drill or even just by hand and observe the voltage from the windings by putting the scope between any two of the motor winding leads. Then switch to another combination. All the winding combinations (A to B, B to C, C to A) should be the same amplitude.

The windings should have good insulation to ground. Normally this is tested at high voltage with an insulation tester but you likely don't have this equipment and if this type of fault occurred it would likely damage the motor control circuit. I would just test for direct shorts with a multimeter and if windings to case show open call this ok.

The encoder can be powered from the motor control (or from a power supply but that requires you determine the power connections and any miswiring could fry the encoder). Dont connect the motor windings. Turn the motor by hand while observing the outputs of the encoder. The most basic check is that they should all pulse high and low. The zero pulse is very short and may be hard to catch. If there is no key setting position is more complicated but possible.

The tach simply outputs a voltage proportional to speed. Mount it on the shaft and spin the motor and observe the DC output increases with speed.

If all that looks good then hook up the motor to the drive and try to run it.

[SEK22Hornet]

There are clamps on the coupler for the tach and on the encoder shaft. No marks or keyways on the shaft. I'm still gathering up hardware to mount everything. 2 of the long spacers are missing so I'll need to make up something - need to check to see if the the threads are metric or imperial. I have some 6-32 spacers I can stack up to get the right length. In #4 you can barely see the two holes you have to work through on the side of the housing to tighten the encoder and tach on the shaft. The wire colors are all spelled out on the encoder label so finding power is easy. Need to look again and see if I'm remembering correctly but I think it is open collector so I'd need a pull up to check it out if it is. Plan on checking the outputs once i get it back together. Also need to release the brake to do that lol.

[Jim27]

That's more like what I expected. Unless you have a timing diagram for the motor and/or control you are going to have to use another of the motors to get the proper timing. No adjustment is needed on the other motor - just measurements of timing to make the one in parts the same. You need a two channel scope with good triggering and a way to spin the motor at low speed - a few hundred RPM works well. I just did a google search and found a good explanation of how this is done.

You need to check timing on the good motor to see what encoder pulses align with what motor phases. You need a variable DC supply capable of supplying about half the rated current to lock the shaft. The exact amount isn't critical but half should solidly lock the shaft without overheating the winding. Ramp the current down rather than just disconnect at the motor to avoid high voltage pulse from the motor inductance at disconnection. They talk about rotating the body of the encoder which doesn't look possible on your motor. I am guessing that one phase energized on the good motor aligns the encoder lock screw with the hole. Do the same on the motor to be assembled and then check timing by spinning and adjust slightly until they look the same. I don't think you have an index pulse or zero pulse to worry about.

How to time Optical Encoder commutation channels to a BLDC motor - Quantum Devices, Inc.

[sportybob]

Just heard back from Bill at CustomMotorsMN.com

"The encoder is not involved with motor phasing and commutation".

sportybob

[SEK22Hornet]

Just heard back from Bill at CustomMotorsMN.com "The encoder is not involved with motor phasing and commutation". sportybob

Thanks Bob - I was planning on contacting them but had not had a chance to yet - that will make it a lot easier to get that motor reassembled. I plan on finding out what they would charge to check the motor out - I would be more comfortable knowing it is working before putting it back into the machine. Dan

[Jim27]

OP stated earlier a wiring diagram didn't match because it didn't have the commutation feedback for the brushless servos. Apparently the motors don't have that either so nothing I said about that applies...

[sportybob]

Hi Jim, This machine has CSM ( Custom servo motors) these motors were early AC type motors and are a little different. ( tach, encoder with hall switches.) yeah, different .

Most ALL other AC motors , Fanuc, Yaskawa, etc will all have the encoder "timed" to the motor phase.
so for, all the other motors your are correct.

sportybob

[sportybob]

Hi Hornet, you should call me.
952-288-6340

sportybob