correct wiring sizes for JMC Servo iHSV57-30-18-36-21 with axbb-e controller

[the great waldo]

Well I finally got my servo motors JMC Servo iHSV57-30-18-36-21 180watt connected and working with my AXBB-E . the question I have is which size wire to connect the motors to the controller ? The continuous current rating of the motors is 6 amps I assume the pulse direction wires from the controller board don't have to carry so much current. What dimension wire would be ok for the + - volts Power supply I have is 48volts 16amps and also have a 48v 10 amp supply (both switching) I have read that these servos don't pull much more than 3 amps while running. Should I use just the 16amp supply or go with both? Should I use a separate 2 core wire for the power to the servos and use a thinner screened wire (how thick?) for the signal steps connection. Obviously wire for cable chains would be used. Any ideas gratefully accepted.

Cheers

Andrew

[Kitwn]

For all practical purposes the current in the signal wires is zero so whatever you have to hand that conveniently fits the connectors will do.

For power to the motor controllers you could Google 'wire current carrying capacity' and find loads of info from a host of different suppliers. Alternatively ordinary mains wire from your local hardware shop should be available with ample rating.

RS Components will sell you a whole host of different multicore cables for the motor wiring but won't tell you the current rating due to a variety f factors which will be explained in many of the results of the above Google search!

[the great waldo]

Hi Kitwin

Thanks for the information. Is it good practice to screen the power cables as well as the signal wires?

Cheers
Andrew

[Kitwn]

I don't think you need to screen the power cables TO the drivers but it's usual to screen the multicore cables going out to stepper motors to prevent them coupling noise into the limit switch wiring. Not sure if it's as critical for servos but should also be done for the spindle cable. Sheaths are earthed at one end only, normally the controller.

It's a good plan to route the power and signalling cables separately within your controller, don't bundle them closely together, and bring all the earth connections to a singe post rather than just connecting to the chassis at the nearest point.

Kit

[AndyUK]

It's a good plan to route the power and signalling cables separately within your controller, don't bundle them closely together

Just to add to this point, I was informed by a chap who is 'Head of Electrical Wiring' at a technology company who produce lots of these large cabinets as part of their product to keep every type of cable as separate as possible: ie Mains AC type cables go on one side of the cab, Low DC go in another, High DC in another, and signals away from it all.

This is why I've tried to layout my cab in various areas; mains AC distribution and switching, then 24V distribution, then Signals, then 68V distribution etc.

[JAZZCNC]

Just to add to this point, I was informed by a chap who is 'Head of Electrical Wiring' at a technology company who produce lots of these large cabinets as part of their product to keep every type of cable as separate as possible: ie Mains AC type cables go on one side of the cab, Low DC go in another, High DC in another, and signals away from it all.

This is why I've tried to layout my cab in various areas; mains AC distribution and switching, then 24V distribution, then Signals, then 68V distribution etc.

This is something which often happens in DIY builds and causes plenty of head-scratching and sleepless nights, The lower the quality of electronics used the more trouble it tends to cause. Tie wrapping signal wires tightly together is also another mistake that causes trouble.!

[JAZZCNC]

Hi Kitwin

Thanks for the information. Is it good practice to screen the power cables as well as the signal wires?

Cheers
Andrew

No it's not needed power cables but like Andy pointed out above you need to pay careful attention to how you route the wires.

For the Signal wires, Ethernet cable is a good choice as it uses twisted pairs and shield. Also, 1 Cable can do 2 drives for Step n Dir or if using Enables etc just one neat cable per drive as it as 8 wires.

[the great waldo]

Hi Jazz

Would ethernet cable be ok for drag chains ? or would cable specifically designed for drag chain use be a better choice ie.https://www.sorotec.de/shop/Control-Cable-OeLFLEX--FD-CLASSIC-810-CY-5-x-0-5-mm-.html or some thing similar ?
cheers
Andrew

Ps. I was shocked at how quiet the servo motors ran (On the bench without load)

[JAZZCNC]

Hi Jazz

Would ethernet cable be ok for drag chains ? or would cable specifically designed for drag chain use be a better choice ie.https://www.sorotec.de/shop/Control-Cable-OeLFLEX--FD-CLASSIC-810-CY-5-x-0-5-mm-.html or some thing similar ?
cheers
Andrew

Ps. I was shocked at how quiet the servo motors ran (On the bench without load)

No not really. But why would you be running signal wires for Servo's drives thru drag chain.? Where are you locating the drives.?

[JAZZCNC]

No not really. But why would you be running signal wires for Servo's drives thru drag chain.? Where are you locating the drives.?

Ok, I've looked up the servos and see the drives are mounted to the motors. In this case, you need a high quality shielded cable and make sure you run it well away from high voltage cables in the drag chain.
This is one of the very reasons why I don't like these types of drive. Essentially you are going to be running really long aerials around your machine which are just looking to soak up any stray voltages and electrical noise passing there way. This can and does cause all sorts of crazy things to happen.

The other is the vibrations that get transmitted through the motors and machine will IMO eventually cause issues. Then you also have to protect them from debris etc.

Yes AC and DC servo motors are very quiet compared to steppers, Silent machine killers when they take off from stray electrical noise.! :hororr::hororr::devilish:

[the great waldo]

Thanks for that Jazz
The machine is not huge 1m x 0.5m so I should be able to keep the wiring reasonably short and well screened. I've got some sealed 3d printed covers for the drivers on board and will also be fixing down cable connections with some hot glue or silicon(not sure which is better but I think hot glue as you can get it apart if need be)

Cheers
Andrew

[the great waldo]

Would there be a problem running the 48v power supplies to the motors using 1 multicore cable for tidiness? Or would 3 separate 2core wires be better?
Cheers.
Andrew

[Kitwn]

You're better using separate pairs for each driver rather than daisy chaining them but I can't see a problem with having those separate pairs bundled up in one sheath. Be aware that thermal considerations may mean using larger conductors in a multicore than 'free' wires with some air round them, and you'll pay more for it as well. Remember that electricity has no sense of aesthetics and a bundle of wires tied together with old old string will perform just as well.

Kit

[the great waldo]

Hi Kit
Thank you. I did think that running the power in one multicore might lead to thermal problems. Separate cables would I think also be more flexible. I'm wondering if I need 1mm or 1.5mm wire for the power side of things. I'm no electrical genius just learning by reading and asking but I think you can't beat advice from somene who has actually done something !

Cheers
Andrew

[the great waldo]

Hi Kit
Thank you. I did think that running the power in one multicore might lead to thermal problems. Separate cables would I think also be more flexible. I'm wondering if I need 1mm or 1.5mm wire for the power side of things. I'm no electrical genius just learning by reading and asking but I think you can't beat advice from somene who has actually done something !

Cheers
Andrew

[JAZZCNC]

Would there be a problem running the 48v power supplies to the motors using 1 multicore cable for tidiness? Or would 3 separate 2core wires be better?
Cheers.
Andrew

Difficult to know without seeing the layout of the machine and control box position etc. But If it was me then I would run a single cable from the control box close to the motors and into a terminal box, then split off from there to each motor. This way only got 1 x 2 core wire running through the machine.


I'm wondering if I need 1mm or 1.5mm wire for the power side of things. I'm no electrical genius just learning by reading and asking but I think you can't beat advice from somene who has actually done something !

You don't really need to be a genius because there are plenty of Cable sizing calculators and web sites explaining correct sizing etc available online if you are unsure. Like this one.
https://www.12voltplanet.co.uk/cable-sizing-selection.html

However, 1mm will work fine for your application with short cable lengths.

[the great waldo]

Hi Jazz
Thank you for your input; I'd assume I should use a heavy guage connection from the control box power supply to terminal block/strip and then split off to individual motors from there with thinner wire.

Cheers
Andrew

Ps thanks for the link to the cable selector. I makes things much clearer

[JAZZCNC]

Hi Jazz
Thank you for your input; I'd assume I should use a heavy guage connection from the control box power supply to terminal block/strip and then split off to individual motors from there with thinner wire.

Cheers
Andrew

Ps thanks for the link to the cable selector. I makes things much clearer

Yes need to size cable according to total current draw.

[the great waldo]

Ok thanks.
Andrew