What is too HOT?

[voltsandbolts]

What is too Hot?

Yes I know there are other threads on stepper motor heating.

What I want to know is how hot are your motors?

Please list any or all :

Motor Size:
Rated Holding Torque:
Voltage / Amps your running at:
Driver Type (Micro stepping or not, settings?)
Lead screw Size and pitch:
Weight of axis being moved:
Temperature of motor idle:
Temperature of motor running:
Your favorite color: (just kidding)

I used to work for a company that made Die sorters and wafer handlers for the integrated circuit industry, we ran our steppers HOT! Like raise a blister hot, Motor sizes 23 and 34 were run at70-75Volts 10 Amps. We used PacSci micro stepping drives I think they were model 6410. I think the holding torque on the 23 motors was 212 in/oz (PacSci power max). And were driving 10” X,Y tables from DCI with 5/8” ball screws. The machines did have muffin fans to help keep the heat down and the stepper drivers had automatic current fall back when the motors weren’t moving.

Forgive all the “I thinks” it was 10 years ago.

So what has your experience been with motor heating?

[Eurisko]

This should be promoted to "sticky thread" status !

Sorry I can't give you any empirical data yet, ( my router is STILL in the planning phase ) but this thread couldn't be more timely.

My gecko G201 drives arrived today. The instructions stated that the Gecko drive's temperature must not exceed 70 deg C (158 deg F).

A non-contact laser thermometer to monitor both the drive temperature AND the stepper motor temperature sounds like a wise investment.

I'm curious, too, if any CNCZoners use active cooling (fans, heatsinks, etc.) on their steppers.

[kreutz]

Stepper motors are designed to work HOT. Manufacturer's specs specify to keep the motor temperature under 212 degrees F (100 degrees C), I like to keep them under 176 degrees F (85 degrees C).

Kreutz.

[voltsandbolts]

Has anyone actually seen degradation in motor performance due to over heated motors? How hot was it? I acknowledge the manufactures have recommended values for heat and that there is most likely a safety factor of X% befor you bake your motor.

What I hope to see here is real world data, and experiences. We may find that cretin brands of steppers take the heat better, and are therefor a better value, or that no body’s running there motors hard enough to worry about it. Who is running a fan on there motors or a big heat sink? I personally run a muffin fan on my drivers to help them stay cool.

You ever know, someone might find this info useful.

[James Newton]

I wasn't going to post this because it will sound like an ad, but since no one else is really jumping on here, perhaps I can offer some small bit of information and offer an incentive to others to collect the data you are asking for. I'm also very interested in the result.

First, I have an obvious bias: I sell a kit for a small OPEN SOURCE Linear driver (the Linistepper) and one of the sales points is lower motor heating due to reduced eddy current losses which most chopper drivers induce as a result of the high frequency component of thier Pulse Width Modulation of the drive current.

Second, I do not have EXACT temperature readings. I wish I did and see my offer at the end of this post.

I have heard from several of my customers that when they run thier motors on a chopper drive, they get good operation at first (not missing steps) but that the motors get very hot (hot enough to burn) and then start missing steps or having other problems such as shorting, melting, or burning out.

When they switch to the Linistepper (or any linear driver) the motors dont get anywhere near as hot (although the drivers DO get hot as all heck) and the motors tend to not miss steps as a result. With the Linistepper, they still get good speed, because unlike standard linear drivers, it actively regulates the current being pushed through the motor coil and so does not suffer from the inductive lag that most older linear designs will struggle with.

You can check out some of the customer comments at:
http://www.piclist.com/techref/io/st...step/index.htm

My offer: If you purchase a kit or set of kits for the Linistepper, build then hook up to your device (mill, lathe, telescope, etc..) and send me a picture of it (clearly showing the Linistepper) I will refund $10 of your purchase price. I will refund an additional $10 for a picture of any item showing the difference between linear microstepping and any of the standard stepping modes. The second refund is only available after the first has been qualified. It can be a picture of two items made by your device or, if you are using the linistepper to control a telescope mount, it might show the difference in clarity between two identical long exposure photos of the stars. Finally, a third $10 refund, available after the first two have been qualified, is offered for temperature readings of the motor and controller after 1 hour of operation in full step mode and again after an hour in linear microstepping mode or after 1 hour of operation from a microstepping chopper controller compaired to the Linistepper in microstepping mode.

That last bit added for this post only. Please note that this means you could effectively pay NOTHING for your kit. As if $30 each ($25ea for three) isn't a low enough price. And the price will be increasing soon.

Hope that helps... I'm very interested to see if any real data becomes available as a result of this thread.

[project5k]

well i just got my 203v's in and just had to hook them up on the desk to make sure that they worked.. good ole oops(ups) really did a # on my box, but after openeing it up, i was pleasently surprised that each of the 3 203's were in a little bubble envelope, and showd no signs of harm.. so i hooked one up with the following. 2 converted "AT" computer powersupplies, ground de-regulated and tied together in series to produce 24vdc, and 1 of my 500oz motors, nema 23, set the current regulation to just over 3A and started playing with mach.. after playing around for about a half an hour, (seeing just how fast i could make that motor spin(my max was 1300rpm according to my laser tach) and running the roadrunner code a couple times at different speeds and accel settings, i ended up with an outter motor case temp of 125F. this was in a room at 70F and no fan.. the gecko203v was a happy 99F on the back plate. this was all done with no load on the motor other than the half a lovejoy that was allready attached.

[voltsandbolts]

Good to see some info starting to trickle in. That’s what I want to see, keep it coming.

[kreutz]

Here are Oriental Motors' guidelines:

"The permissible temperature for the coils is 266 F (130 C), since the insulation of the motor is Class B. The motor can be used if the motor surface temperature is 212 F (100 C) or less. Try to use the motor at the lowest temperature possible and mount it to a metal plate that is a good heat conductor, since heat does affect the life of the motor's ball bearings. Type A insulation 221 F (105 C) is a UL/CSA certification condition."

As I said before, I like to keep them under 176 degrees F (85 degrees C). But if you are appliying for UL/CSA certification, try to keep them under 75 degrees C (167 degrees F)

[Cartierusm]

I asked this questions last week. Here's the data I came up with, especially for all those people curious about a device that is supposed to run hot.

I have 425 oz. Keling Stepper Motors.
5056 Keling Drivers
24V DC

During a run I used a laser thermometer to test results.
The hottest it ever got was 132 Fahrenehit.
Normal during the run was 115-120 F.

Hobbyshopcnc's website FAQ say it can sustain temps of 194 F (90 C).

[kreutz]

Look at the temperature readings on this video (degrees C). It is the same motor you have. Power supply voltage is 35 Vdc.

[Cartierusm]

Same Motor as whom? Me? What were we supposed to gather from that video. His temp said 47 I take it that's Celcius? That translates to about 116F, just about in line with my readings but his were not taken under load or cutting, mine were. How do you know what motors he is using? If you do know, do you know what he has for acceleration and velocity in Mach 3, I wish I knew what other people were running theirs at because I think mine are running slow. But then again I'm only running 24V.

[kreutz]

Same Motor as whom? Me? What were we supposed to gather from that video. His temp said 47 I take it that's Celcius? That translates to about 116F, just about in line with my readings but his were not taken under load or cutting, mine were. How do you know what motors he is using? If you do know, do you know what he has for acceleration and velocity in Mach 3, I wish I knew what other people were running theirs at because I think mine are running slow. But then again I'm only running 24V.

I know it is the same motor because I am the one who did the test. Motor is a Keling 425 oz-in, 6.8 mH per coil, connected to a Mardus-Kreutz Board. Adjusted current 2.82 Amperes peak. Automatic Torque compensation on the translator board compensates the r.m.s. current for all micro-stepping modes. Motor power supply adjusted for 35 volts. Used Mach3 demo edition for testing.

The speed: In this other video I stopped at 3968 rpm because I could not control the rotation on the motor support to keep under the camera field. .

Those tests were done when the maximum kernel speed with Mach3 was limited to 45 khz. The temperature is supposed to increase quadratically with the Power supply voltage. Newer tests with 82 V power supply show that increase, and also unbelievable torque, moving an X1 with 20 tpi original lead-screws, nuts and gibbs at 97 ipm. Cutting at that speed was not tested due to spindle speed/power limitations.

Note: Motor heating is higher when the motor is used at low rpms or even when iddle, if no current reduction feature is available, at high speed the current on the coils never reach the maximum current, also the current chopping disappears (and with it almost all associated magnetic losses)

Regards,

Kreutz.