Need Help!- Question on Gecko G540

[blackonblack]

I plan on assembling my first machine within the new few weeks. I picked up a Gecko G540 and I plan on purchasing a K2 Chassis. I have read the manual as well as many other sources of CNC build info but I have a few questions. The Gecko manual says "The motor’s rated phase current must be between 0 Amps and 3.5 Amps". Does that mean TOTAL amps or just the listed amps on the motor because there is a difference in the amps depending on how the engine is wired. The motors I plan on using "Probotix Green Monster" list 4.2 amps of current when wired in parallel. Does that mean I cannot use these motors when wired in parallel? The unipolar wired current draw is listed at 3 amps, within the range.

Also when choosing the correct current set resistor for the motors, do you go by the MH rating indexed for the wiring configuration you are using?

[ger21]

Use the rated current for the motor, the 4.2 amps in this case. Torque is proportional to current, so if you used that motor, you'd get 3.5/4.2 or 83% of the rated torque.

However, that's a poor choice of motor for the G540. A much better choice is the Keling KL23H2100-35-4B. You'll get much better high speed performance, and, it's $20 cheaper.
http://www.kelinginc.net/NEMA23Motor.html

[Crevice Reamer]

Hi BOB. Welcome to the Zone!

Gerry is right. Here's what I recommend:

http://crevicereamer.com/Page__57.html

CR.

[blackonblack]

Thank you both for the information. I was further reading the Gecko manual and it stipulates that your power supply should be 32 x the square root of the MH of the motor which KL23H2100-35-4B has a MH rating of 2.8. yielding a recommended voltage of 53.5 volts which is above the safe range the G540 can handle. What power supply would you guys recommend if I plan on running 5 of those mentioned motors with the G540?

[ger21]

48V

[blackonblack]

Originally Posted by ger21 48V

Ordered. Where is a source to get a couple 3.5K 1/4 watt resistors for these motors?

[Crevice Reamer]

I would and do use 50V. Uh, the G540 can only run 4 motors though.

CR.

[Crevice Reamer]

Originally Posted by blackonblack Ordered. Where is a source to get a couple 3.5K 1/4 watt resistors for these motors?

Digikey has a 3.48K that fits the bill. Their link is in the link that I gave you.

CR.

[blackonblack]

Originally Posted by Crevice Reamer I would and do use 50V. Uh, the G540 can only run 4 motors though. CR.

Correction 4 motors woops.

[Crevice Reamer]

BTW, If you are buying a 48V switching PSU, it probably has a Voltage adjustment and can be upped to 50V.

CR.