300NcmMotorTermination

Created by: Lester Caine, Last modification: Sun 31 of Jul, 2011 (15:59 UTC)

This provides the information for adding a screened 4 way power lead to a stepper motor. The pictures provided are based on the newer 300Ncm motor which is quite a bit more powerful then the similar sized 180Ncm unit. The 4 pin XLR style connector is suitable for use up to 10amps and provides a reliable, locked connection to the driver socket. The cable screen is not connected at the motor end, but should be linked to mechanical earth at the driver end.

Click on any picture to view a higher resolution version.

3NmStepperMotor
( Copy of mechanical drawing to be included )

This stepper motor comes with a plastic molding around the flying leads which is a little more difficult to terminate that the more normal simple un-terminated wires. This need a slightly different arrangement on the mounting box, with a slot in the end rather than a simple hole in the back.
3NmBoxSlot
The box then slides up against the moulding hiding the wires. A second 9.5mm in the side provides the entry point for the cable.
A 20mm length of Epoxy Putty is about right to secure the box leaving a neat filet around the base. Uses a small off-cut of putty to fill the gap between the box and the wire housing, ensuring that the housing is secured in place.
3NmStepperMotorMask 3NmStepperMotorEpoxyPutty
The cable gland is not fitted until the box is attached to the motor, once the epoxy putty has set. (Leave Overnight to cure).
3NmStepperMotorBox 3NmStepperMotorCable 3NmStepperMotorCableTerminated 3NmStepperMotorCableHeatsink
Cut back about 30mm of sleeve, and un-braid the screen to provide a screen tail. This will not be used, but is left available if it becomes necessary to provide an earth connection to the motor. Normally the screen is only earthed at the plug end. Strip the four wires to provide a 5mm soldered tail to solder the two motor wires to. We are assuming that the motor will be used in parallel mode. Once the tails have been soldered to the wires, a small piece of heat shrink sleeve should be applied to each joint. A cable tie is secured to the cable to act as a strain relief, before the ends are packed into the box, and the lid fitted.
Pin out for cable.

1 Red connects to motor Red Blue
2 Yellow connects to motor Yellow Black
3 Green connects to motor White Brown
4 Blue connects to motor Green Purple

( Cable colours vary from motor to motor, check the pin out against the supplied data sheet if using a different manufacturer supply )

3NmStepperMotorBoxTop
Plug Assembly
CablePrepare PlugTerminate 4pinXLR pins CablePlug Earth
The other end of the wire is prepared in the same way, ready to be fitted to the plug. The cable clamps need to be fitted to the cable prior to soldering the wires into the plug. The earth tag is connected to the screen tail, and has a short length of tape fitted around it to prevent shorting out to pin 1 or 4.
PlugClamp PlugAssemble
Once soldered, the inner cable clamp is aligned with the rib on the plug prior to sliding into the plug shell. The rib, must align to the groove in the shell for the two to fit, but some force will be required to pass the earth clip into the shell. Once pushed home, the rear cable clamp can be screwed onto the shell securing both cable and plug inner.

Fully Assembled

3NmStepperMotorAssembly