How hot is too hot?

[Ernie34]

I am in the process of building my first cnc router. I have the G540 with 4 Nema23 steppers and a 48v power supply. I am just running bench tests right now with the g540 mounted in a metal box to act as a heatsink. Last night I was running a file just to get used to Mach3. Anyways during bench run my steppers were up to 160 degrees f. and the G540 was at 120. Is this just because the motors are not mounted to a structure to pull heat away or are they just running hot?


Thanks!
Ernie

[CalG]

If you are worried, put a fan on the devices. Vent the box, run a cold water line from the ice box ;-) do what you must. electronics hate heat.

[Mariss Freimanis]

Please see:

http://www.geckodrive.com/upload/G54...Experiment.pdf

Mariss

[Ernie34]

Hi Mariss,

Not so much the G540 I was concerned about but more the motors. Under a no-load condition they were at 160f. This is my first time using steppers of this size and it seemed a little alarming to me to be that hot. Im thinking that its because they are just sitting on a bench not bolted to anything to act as a heatsink. Im pretty sure once I get them mounted to the machine the mounts will dissapate the heat away from the motors. I hope!!!! lol



Ernie

[TMaster]

160F seems hot for no load. I've measured 130F to 155F (55c to 68c) on my 2.8A 269oz motors after 1 hour running my cnc machine, using a 48V psu and G540. That was with loads.

My motor specs say they can handle a max of 212F or 100C. So this seems to be ok.

I don't think mounting the motors will help much for the heat. I would get it all setup and running then check the temps with loads. Report back with your findings.

I need to run a few tests with my setups also. Could be pointless but I like to get to the bottom of things no matter what. Here's the thread:
http://www.cnczone.com/forums/showthread.php?t=94264

[TarHeelTom]

Don't have everything mounted yet, but I've got a piece of 1/2" x 3" Al long enough to screw the 4 Geckos to, and then a couple of 2 1/4" x 4 1/4" heat sinks with 5/8" tall fins.

Suspect I'm going to mount the Geckos, the pdx-132, the slab, and the heat sink in the back cabinet on the mill. This cabinet has a blower pushing filtered air into the cabinet, and plenty of vent holes for it to escape. Haven't crossed the bridge of where to mount a computer fan to directly cool the heat sink, but there's plenty of room.

I'm thinking it would be interesting to mount a thermocouple to the slab of Al and feed the output from the thermocouple back to the computer screen, or perhaps just a stand-alone temperature readout.

Anyone got any suggestions as to where to source a thermocouple and readout?

Tom

[rowbare]

There are a bunch available on eBay. I had one on my watch list from the seller sureelectronics1 item 350356750304. It is a bit limited in range because of the display but if you can live with celsius it could do the job. There is also a fancy looking one for PC modders that looks almost like an LCD version of a VU meter: 110538372052


bob

[Crevice Reamer]

Originally Posted by Ernie34 I am in the process of building my first cnc router. I have the G540 with 4 Nema23 steppers and a 48v power supply. I am just running bench tests right now with the g540 mounted in a metal box to act as a heatsink. Last night I was running a file just to get used to Mach3. Anyways during bench run my steppers were up to 160 degrees f. and the G540 was at 120. Is this just because the motors are not mounted to a structure to pull heat away or are they just running hot? Thanks! Ernie

Hi Ernie. What motors are you running? What is their Amp per phase rating? How are they wired? What size current limit resistors are you using?

CR.

[Ernie34]

Im running the 380oz, Nema23's from CNCRouterparts.com. 48v stepping power supply and a G540 controller.


Ernie

[Crevice Reamer]

Well, then, they are wired Bipolar parallel and have 3.5A resistors already installed. That means the Idle current limit circuit should be operating normally. They will probally run a little cooler when mounted and under load. Anything under 180 degrees F. is good stepper motor temp.

CR.

[charliel]

Originally Posted by TarHeelTom Don't have everything mounted yet, but I've got a piece of 1/2" x 3" Al long enough to screw the 4 Geckos to, and then a couple of 2 1/4" x 4 1/4" heat sinks with 5/8" tall fins. Suspect I'm going to mount the Geckos, the pdx-132, the slab, and the heat sink in the back cabinet on the mill. This cabinet has a blower pushing filtered air into the cabinet, and plenty of vent holes for it to escape. Haven't crossed the bridge of where to mount a computer fan to directly cool the heat sink, but there's plenty of room. I'm thinking it would be interesting to mount a thermocouple to the slab of Al and feed the output from the thermocouple back to the computer screen, or perhaps just a stand-alone temperature readout. Anyone got any suggestions as to where to source a thermocouple and readout? Tom

I purchased aquarium thermometers on EBAY (search for "Digital LCD Fish Aquarium Tank Water Thermometer"- firstwell is selling for $1 plus $1.99 shipping from HongKong (less that $3 each)-I bought five-one for each controller and an extra. They vary in their readouts by a degree and a half (five set on a shelf next to one another), but that should be close enough to tell between, e.g., 150F and 155F.

Charlie

[Ernie34]

Here are the motor specs. Im sure that once I get it under load and mounted to the machine to act as a heatsink it will run cooler.


Ernie