[bucky898]

The Y-axis servo motor on my IH CNC mill has died for the second time. I get no response from IH, either on their main number or Tommy's cellphone. I'm wondering if anyone knows a source for a compatible motor? I pulled mine from the aluminum housing and it has no markings whatsoever; no manufacturer, no model number.

I can buy something similar on the web and make it fit, but if anyone has a specific mfg and model, that would be great.

Bill G.

[Al_The_Man]

What actually is failing on the motor? If this is known you may be able to prevent it in the future.
If you obtain the physical dimensions and the supply voltage, i.e. power supply DCV.
A source of small DC motors is CMC, these are often listed on ebay.
Al.

[Cruiser]

I am told that these are custom motors that Aaron had made for the design and what burns them out is hitting a hard stop in a stall. They will smoke almost immediately if they hit a hard stop and power is still trying to move them. I have a spare that I intend to keep for just such an occasion. I smoked two of the Y axis after going through limit and then dumb thumbing it the wrong direction to drive it away from stop. I fixed that issue so it shouldn't happen again.
The fix for me is having the soft limits properly setup and keeping it turned on at all times.

[BobWarfield]

FWIW, my HomeShopCNC servos fit the IH brackets just fine. The Z is finicky, but X and Y just bolt up.

You can see more on my site:

http://www.cnccookbook.com/CCMillCNCHome.html

They're also a bit more powerful, and I can say from experience they won't burn out from a hard stop. Now I do have a CNC4PC board that will shut down power on a servo fault, so that helps too. I wouldn't want to just let them sit there for a prolonged period against a stop not being able to move.

Best,

BW

[Runner4404spd]

the IH motors don't burn out when they hit the stops. if they do i think your tuning is off. you could also try adding a fuse to the inline power wire on the motor. i dont know if that will adversely affect the gecko but it shouldn't. you would ultimately have to hold the motor at a rapid speed for a long time against the stop to draw enough current to burn out the motor.

[RustedOut]

I never got IH motors for my conversion, but did install the 850 oz.in. HomeShopCNC servo's as well. The NEMA bolt pattern is drilled in both the motor and the servo mount from IH. I went ahead and slotted the mount so I could adjust belt tension.

Also made some custom 16 tooth 5mm pulleys to mount on the 1/2" motor shafts and cross pinned them to the shaft. Managed to use the IH belts that way. I did X and Y this way. Pulley ratio is 3-1 instead of the IH 4-1, but the servos pull pretty hard and hasn't been a problem so far.

I have some extra of these pulleys that I would be willing to part with. I never found a commercial source for them. They make it an easy swap.

Bob

[ksanalytical]

Bill,

How long have you had your mill? I'm just curious as my turnkey is supposed to ship early next week. After seeing the little servos while visiting the shop I confess that I've considered swapping out to the large 850 motors right out of the gate. I have 5 of them with 7:1 gear reduction heads on the shelf and from initial tests, they seem extremely powerful and smooth.

I initially tested them with the "limit" set very low and any hard stop I created (by grabbing a pinion gear) caused an immediate fault on the servo. I'm surprised to hear that it's even possible to burn up a motor while this control is in place...

Ken

[Cruiser]

Bill,

How long have you had your mill? I'm just curious as my turnkey is supposed to ship early next week. After seeing the little servos while visiting the shop I confess that I've considered swapping out to the large 850 motors right out of the gate. I have 5 of them with 7:1 gear reduction heads on the shelf and from initial tests, they seem extremely powerful and smooth.

I initially tested them with the "limit" set very low and any hard stop I created (by grabbing a pinion gear) caused an immediate fault on the servo. I'm surprised to hear that it's even possible to burn up a motor while this control is in place...

Ken

Those little servos have enough power to snap large end mills and push parts out from under clamps !

[jdclark]

I am told that these are custom motors that Aaron had made for the design and what burns them out is hitting a hard stop in a stall.

Highly unlikely that a limited market like this could have motors custom made. More likely they found some off the shelf motors and added encoders. Surplus center was selling some servo motors a while back for 29.00 each, but the supply has run out. It could be part of their current problems, as you cannot set your pricing and specifications around a limited supply.

[bucky898]

On the mill, the Y axis wouldn't move but the Mach3 DRO would increment and the Gecko fault light was on. Same behavior as when the first servo died. I pulled the servo and connected it to a power supply. The rotor was dead for most of the 360 deg. rotation as I turned it by hand, but there were spots where it make a connection and spin for a bit. I assume there are one or more open windings. I pulled the brushes and they and the commutator look OK; there's still plenty of length left on the brushes. I haven't crashed the axis into a stop or anything like that; I've just been running some fairly tame and low-speed jobs.

I've had the mill for less than a year. The first Y servo failed within a month or two.

[Al_The_Man]

Generally the reason for Servo failure that has not seen alot of service is overcurrent,
This can be persistently reaching peak torque current through accel/decel modes that exceed the motor rating.
This will either take a couple of windings out or demagnetize the field.
Motor undersizing and drive over-current settings that are incorrect or Drives that do not posses OC limit protection are a prime cause.
Al.

[skullworks]

the IH motors don't burn out when they hit the stops. if they do i think your tuning is off. you could also try adding a fuse to the inline power wire on the motor. i dont know if that will adversely affect the gecko but it shouldn't. you would ultimately have to hold the motor at a rapid speed for a long time against the stop to draw enough current to burn out the motor.

If you are suggesting a fuse between the gecko and the servo, if that fuse ever blows, so will the Gecko.

Even on the power input side a fuse feeding the Gecko should have a diode bridging the fuse to allow a power return path when the fuse is blown.

Gecko's don't like inrush surges, so gecko recommends only switching the AC power to your powersupply, never the DC on the output side.

[powerr]

bucky898 did you find a replacement. if not could you post a picture of the motor pulled out of the aluminum case. if it is the same as the version 2 kit. then i think they are made by Pittman motor. and the can be ordered with custom voltage and current ratings. that is the only problem, wouldn't know what to order from them. it would probably be cheaper to by a servo from homeshopcnc or keling . and you say this is your second motor on the Y axis something sounds wrong.

Rob