[bogdanalex]

Hi everybody!

I have a cnc which run with THB6064 drives and the above motors :

Minebea 23PM-C108 6 wire unipolar ( series setup )
5.4V / phase
1.5A / phase

I have set the driver to 1.5A , half step , and powered with 28V PSU however at a 5 minute job with not a big deal of a load, the motors overheats.
In which way can I fine tune the setup for the motors to stay cooler but at the same time not to loose a great amount of torque?
Does the decay settings of the driver can have an impact on this matter ?
Or maybe using a half-coil setup worth trying ?!...although I am aware of the change of torque behavior.

[H500]

If the motor rating is 1.5amp unipolar, you will need to reduce it to 1.1 amp for bipolar series. However, the half coil modeat 1.5a will almost certainly give you better performance, even though the static torque is less. What is the supply voltage? The higher the better, but don't exceed 40v or so.

[James Newton]

Didn't we reply to this last week? 1. Get bigger motors, 2. yes half coil, 3. add CPU fan heatsinks with paste to the motors.

[bogdanalex]

@H500 - for now I'll try to lower the current to 1.1Amp cause is the most convenient measure. If it doesn't solve the issue I'll go with half-coil @ 1.5A . As I said, motors voltage is 28V

@James Newton - Bigger motors are not an option for the moment...maybe in the future. I'll try half coil as soon as arrives some connectors that I've ordered. CPU heatsinks are hard to mount because my motors are cylindrical....maybe I'll try with some small radiators glued with sticky thermal paste.

[lucas]

@ James: I did in another thread but lacked time to reply with details.

@ Bogdanalex:
There's no datasheet for the motor,so it's difficult to give exact settings.
Simple method is to adjust the current for a max motor temperature of approx 60°C.
You can evaluate the series connection by reducing the motor current as suggested.

However there's the Voltage/Amps per coil ratio which is quite high compared to modern good motors, this is an indication that the coil inductance will also be relatively high.
The series connection might be not satisfactory: if not try half coil (as suggested) and/or increase the supply voltage.
You will need stronger motors if the above fails.