retrofit on EMCO PC turn 55

andypugh wrote:

jrkeat wrote:

Where did you read this?

It isn't in the Rev 8 manual (interestingly)
But: www.geckodrive.com/gecko/images/cms_file...%20MANUAL%20REV1.pdf

"1) MOTORS: One to four step motors are required. All NEMA-17, many NEMA-23 and a few NEMA-34 motors are
acceptable. The motors preferably should be square in cross-section, not round. The motors can be 4, 6 or 8-wire
motors. 5-wire motors cannot be used with the G540. Choose a motor that has a rated current of 3.5A or less.
Choose a motor that has a rated winding inductance of 2.5mH to 3mH if maximum power output (>100W mechanical)
is a requirement. Never use a power supply voltage greater than 32 times the square-root of the motor inductance
expressed in milli-Henries (mH)."

It might be something that would need to be checked with Gecko, as they have changed the drives since that document was written.

It would probably be easy to convert the motors to be 6 wire--I'll see when they get here.

I thought my old motors went out in the scrap but it turns out I still have them. One is fully disassembled and the other just has the back off.

There is a terminal block in the back of the motor with 10 terminals. 5 of the terminals are tied together (and there is no connection wire on the common bus). The other 5 terminals have wires connected to them.

On the motor side of the terminal block there are 10 wires connected to 10 terminals on the stator coils. This seems to indicate there are 5 indiviual coils and one side of each coil is common.

I will leave it up to you guys to decide if this motor can be converted to a useable configuration. Personally I don't think so.

chuck1024 wrote:

This seems to indicate there are 5 indiviual coils and one side of each coil is common.

Ah that _is_ interesting and might indicate that these are 5-phase stepper motors. Apparently they are quite nice and rather smooth.

Stepgen types 11 to 14 are for 5-phase stepper motors. However, that just drives 5 output bits, which is only part of the answer as you still need the current-control PWM.

Sounds like a 5 phase step motor in star configuration
Note that a dissasembed step motor is usually destroyed by dissasembly
(if the rotor is removed)

chuck1024 wrote:

I thought my old motors went out in the scrap but it turns out I still have them. One is fully disassembled and the other just has the back off.

There is a terminal block in the back of the motor with 10 terminals. 5 of the terminals are tied together (and there is no connection wire on the common bus). The other 5 terminals have wires connected to them.

On the motor side of the terminal block there are 10 wires connected to 10 terminals on the stator coils. This seems to indicate there are 5 indiviual coils and one side of each coil is common.

I will leave it up to you guys to decide if this motor can be converted to a useable configuration. Personally I don't think so.

Thanks for the info!

They're still useable, but cuts off the simplest solutions. (5 phase stepper controllers exist, but are much harder to find--the Techno Drive KR-5M is available on Ebay right now). If the manufacturers' claims are to be believed, there are many advantages to the 5-phase motors: www.orientalmotor.com/technology/articles/2phase-v-5phase.html --lower vibration, higher precision, etc.

PCW wrote:

Sounds like a 5 phase step motor in star configuration
Note that a dissasembed step motor is usually destroyed by dissasembly
(if the rotor is removed)

It doesn't look like I'll have to disassemble anything--it up to me to decide if I want to drive a 5-phase or not. (Or get the existing electronics to do it.)

Out of curiosity, how does disassembly destroy the motor?