Bad TM1 stepper motor?

[MoparJon]

I have a Torchmate 1 which I purchased new as a kit about 3 years ago. I just recently noticed that I seem to have a problem with the stepper motor on my Y carriage.

Long story short, I was having a problem cutting diagonal lines, and I narrowed the problem down to the Y stepper motor. Basically, every time the Y carriage had to change direction, there would be a delay from the time when the computer told the motor to move until the time that the motor actually started to move. The motor doesn't seem to be losing steps, it "catches up" and moves the proper distance, it just takes a fraction of a second for it to start moving, and this seems to only happen when changing direction (i.e. if it is travelling in a Y+ direction, stops, then moves Y+ again, there is no delay. However, going from Y+, stop, then Y-, and there will be a delay upon starting to move Y-. Same thing for moving Y- to Y+.)

Whenever the signal controller is on, my X axis motor makes a slight humming or buzzing noise. (I assume this is normal?) The Y axis motor makes a louder noise, and it is not a constant buzz, it is a bit intermittent, there are some occasional clicks and such too. Also, the Y axis motor runs hotter. I have had the signal controller on for the past hour or so, not moving the motors, just sitting idle. Ambient temp is about 75 degrees F, the X axis motor is 81 degrees F and the Y axis motor is 92 degees F.

I swapped my X motor over to the Y carriage, and it did not exhibit any of the delay which the Y motor does, so that seems to eliminate the signal controller or cables.

It seemed pretty obvious that there was something amiss with the Y axis motor, so figuring I didn't have much to lose, I removed the 4 screws holding it together and took it apart. I was surprised at how simple it was; I was expecting some controller type electronics in there but its just a magnet and a bunch of windings. Some of the adjacent windings looked like they were pretty close to touching each other, but checking the windings themselves for continuity did not result in my being able to get a reading, so I am assuming that these copper strands have some sort of epoxy covering to insulate them, in which case, it shouldn't matter if they did touch. I didn't see anything obviously wrong like burnt wires, metal filings, etc. The only thing I saw which I wasn't sure of was that the aluminum caps/bearing supports seemed to be touching the metal bits in front of the windings, I don't know if that is normal or not. I thought about taking the X axis motor apart to compare it, but at this point, I didn't want to risk messing the good motor up in the process. After taking the motor apart and putting it back together, I tested on the gantry again, and it still has the delay problem.

I don't see any part numbers on the stepper motors; the configuration sheet that Torchmate sent with the unit says that the Model Number is 5000-079-111005, but I'm not sure if that refers to the signal controller or the motors themselves. The same sheet also lists axis 1 through 3 as being configured the same, as follows:

Drive model: 2035
Phase current: 1.625A
Step resolution: 400
50% idle current: Y



So anyway, that's what is happening... Does it seem reasonable that my problem is with the Y axis stepper motor? If so, do the symptoms described seem to indicate any particular problem which I might be able to solve myself by dissasembling the stepper further, or am I looking at purchasing a new stepper motor?

If I need to purchase a new motor, what's the best route? Directly from Torchmate? If someone from Torchmate is reading this and could quote me a price, that would be helpful. Also, should I stick with the same stepper motor, or are there plug and play "upgrades" available which might give me more torque/longevity/etc?

For all I know, this may have been happening since day 1; that Y axis stepper has always been louder than the other one. I haven't cut out very many designs, the ones I have done before were more "art" style, as opposed to what I am trying to do now (precision brackets), so I may have just not noticed it until recently. If that is the case, maybe the stepper was just defective to begin with and a replacement of the same model would be the best route. The carriage moves relatively easy without any noticable binding and such, so I don't think the loads on the motor were excessive, plus the machine has only seen light use, so hopefully I just got a bum motor from the get go as opposed to the stepper having worn out?

Any info or advice would be greatly appreciated. Thanks!

-Jon-

[Mike@Torchmate]

If the problem always follows the motor 100%, then I would associate it with a motor or motor cable problem (such as the pins in the connector) and would go along the assumption that your diagnosis is correct.

Depending whether or not the motor is in warranty, you can purchase a replacement, or if you are looking for an upgrade, I might suggest 264 oz in motors if you don't already have them.

[MoparJon]

Thanks very much for the reply, Mike!

According to my invoice, I purchased the TM1 on 8/31/05 and I think the motor warranty is 1 year, so sounds like that option is out.

According to the packing slip received with the kit, I have 135 oz. in. motors. Would the 264 oz versions be a direct plug and play? (same electrical connector, mounting pattern, shaft size, physical dimensions, etc?) If not, what modifications would I need to make to be able to use them?

Are you able to quote me a price on a replacement 135oz motor as well as a price on a pair of 264oz, or do I need to contact someone else for that?

Thanks!

[Mike@Torchmate]

I would give us a call and get a hold of the parts department for quotes on both.

The 264 oz in motors are the same shaft, connector, and mounting pattern, just a bit taller on the motor. It shouldn't give you any interference problems.

[MoparJon]

Thanks, Mike! I'll check with sales for the prices.

I'm not sure that sales would have this info, so I'll ask you - regarding the additional length of the 264oz motors over the 135oz, do you have an exact measurement of that? I've only got about 3/16" clearance between the 135oz motor and the frame of the gantry. If the 264oz motors are longer than that, I think I could still use them by flipping the motor around so that it attaches to the other side of the bracket. (This would also require welding a new mount for the motor plate onto the gantry in order to create enough clearance for the belt pulley to go on the rack gear side of the motor mount, so I've got to take all that into consideration along with the price to see if it is going to be worth the upgrade.)

Also, are there any changes required to the RS232 driver box or the software to use the larger steppers?

As long as we are on the subject, is there a reason why the TM1 has the motor mounted on the gear rack side of the motor mount plate for the X axis? Torchmate obviously went through the trouble of trimming off the axle coming out the back of the stepper motor so that it wouldn't contact the frame, is there a reason why they didn't design it with the belt on that side, which would create all sorts of room for the stepper on the other side, to the inside of the machine? Seems like I have seen pictures of some of the fancier machines (TM2-4) with that arrangement, but I don't know if that was a Torchmate design them or an end user modification. (Just wondering if there is a potential problem to be aware of if I were to flip the motor around.)

Thanks again!

-Jon-

[MoparJon]

It seemed pretty obvious that there was something amiss with the Y axis motor, so figuring I didn't have much to lose, I removed the 4 screws holding it together and took it apart. I was surprised at how simple it was; I was expecting some controller type electronics in there but its just a magnet and a bunch of windings.

Just wanted to reply to myself in case someone stumbles across this thread in the future. I didn't know it at the time, but you should NOT dissasemble a stepper motor. Well, apparently it is generally OK to just pop one of the end caps off, but if you remove the rotor from the stator, you can/will damage the magnet. Depending on the motor, this may render the motor inoperative or may only result in a decrease in torque. Almost certainly it will degrade the motor somewhat, even if that change isn't obvious. If you have the proper equipment and know how to use it, you can remagnetize the motor to restore it to as-new specs, but failing that, please be aware that you are taking a risk whenever you dissasemble a stepper motor. Maybe it will still have enough torque for your application afterwards, or maybe it will not work at all...

-Jon-

[MoparJon]

I would give us a call and get a hold of the parts department for quotes on both.

The 264 oz in motors are the same shaft, connector, and mounting pattern, just a bit taller on the motor. It shouldn't give you any interference problems.

Just an FYI for anybody who might be following this thread. Torchmate quoted me $225 each for the stepper motors (the price was the same for the 135 and 264 oz-in).

That was a bit steep for me, so instead I bought a pair of KL23H276-30-8A steppers from Keling Inc (kelinging.net). These are 282 oz-in motors with the same mounting pattern as the Torchmate units (NEMA23), but for 1/6 the cost; $90 shipped for the pair. The Torchmate stepper motor controller for my TM1 machine (which is actually a FlashCut CNC motor controller, which is actually three Applied Motion 2035 stepper drivers plus power supply in an enclosure) came configured for 1.625 amps. The Keling motor is rated for 2.1 amps when wired in bipolar series mode (which is how I wired it), so I adjusted the dip switches on the X and Y stepper drivers to their max output of 2 amps. The Torchmate/FlashCut CNC steppers use Molex Mini-Fit Jr. 6 pin connectors. I purchased some connectors and the appropriate pins at Allied Electronics for a few dollars, so that I could plug the Keling motors into the Torchmate harness. (The Molex part number for the connector on the stepper motor is 39-01-2060, I believe. I'm not down in the shop right now to be able to check, but the above info should get you to the right page in the catalog; if anyone is interested in the exact part numbers for the connectors and pins, just let me know and I'll look it up.)

The new motors are longer than the stock 135 oz-in Torchmate motors; this wasn't a problem for the Y axis, but because I followed the Torchmate plans when building my gantry, my motor was sandwiched between a 2" square tube and the motor plate, and there was barely room for that little motor, let alone a longer one. I cut the mounting tab off the gantry and moved it a bit so that I could orient the motor on the other side, this allows me to use the longer motor in that location.

This setup works great. The Keling motors are fast and powerful. When I first installed them, I played around a little bit, and I could run them much faster than the 135 oz-in Torchmate motors. 400ipm was easily doable, but the motors did start to wonk out somewhere around 500-600ipm. I set the max speed to 300ipm which is much faster than I need to move, yet still quite conservative as I think 400ipm rapids would probably not be an issue. I calibrated the table after the stepper motor install and it is accurate to under 1/16" in both X and Y directions, for the full length of travel.

The only problem I had through the whole process was when I bolted one of the Keling motors to the Torchmate provided motor mounts; the holes in the mounts were a bit large, which didn't provide enough support to the corner of one of the motor's end plates, and the aluminum end plate cracked at one corner as I was tightening it down. A set of thin washers between the motor and the plate solved this problem. I contacted Keling to see if they offered a replacement plate, but the reply (in broken english) said that they did not. That was a bit dissapointing, but I guess I can't complain for the price. I can buy 6 of these motors for the cost of one Torchmate stepper, which has half the torque. I haven't bothered to replace the motor, as it is still well secured to the plate and the one cracked mounting ear hasn't seemed to create any ill effects.

Anyway, I just wanted to give a quick update and a data point for an alternate stepper motor configuration that will work on a TM1; might be useful if someone finds themselves in a similar situation, needing to replace a stepper motor; maybe it will save you some money.

[MoparJon]

(The Molex part number for the connector on the stepper motor is 39-01-2060, I believe. I'm not down in the shop right now to be able to check, but the above info should get you to the right page in the catalog; if anyone is interested in the exact part numbers for the connectors and pins, just let me know and I'll look it up.)

I happened to come across those part numbers, so figured I'd post them here in case anyone is interested. The male connectors on the Torchmate motors are Molex Mini Fit, Jr. The Molex part number on the connector is 39-01-2060, the pins for the inside are Molex 39-00-0039. Just as a point of reference, in case you want to make an extension cable or something, the female connector for the above is 39-01-3069 and its pins are Molex 39-00-0041. Although these are 6 pin connectors, only 4 are actually used. I purchased all of the above from Allied Electronics, though they should be fairly universally available.

[TAProwler]

Great detective work Jon!

I really appreciate you sharing this info. I have a TM1 too and I'm going to print this info for future reference in case I ever need to replace a motor.

I can understand making a profit, but 6 times other RETAIL prices - wow!

Thanks for the heads up.

[Shapenfab]

Hey, Thanks for this information, I just stumbled onto this post this morning and I too am printing it all out and putting it with my TM folder in the file cabinet just in case a motor needs changing sometime in the future. So far things are working fine. But thanks Jon for all the info.

[Shed Hunter]

jon,

Thanks for the info. I received my connectors to make a power cord. I am hoping it will be obvious when I take the controller apart (not near the controller right now).

Sorry for the novice question. I am wondering how you wired it? Do you remember what ports you used for A+, A-, B+, B-?

Thanks

[Shed Hunter]

Took a look last night. Nevermind, pretty easy! lol