Best way to wire up 4 motors to a 4QD controller

[Michael CallaghanParticipant @michaelcallaghan68621]

Hi, can anyone let me know the best way to wire up a two motor per bogie electric locomotive to a 4QD controller. So far I have been able to get one motor per bogie running. How do I manage to get the others working. Thanks

[Stuart Smith 5Participant @stuartsmith5]

It depends on the battery and motor voltage.

If they are all 12v or 24v wire them in parallel.

If you have 2 xx 12v batteries, you can wire the batteries in series to give 24v into the controller.

If your motors are 12v, wire the 2 on each bogie in series and then the wires from each bogie in parallel.

Make sure you set the link in the controller to the correct battery voltage.

Stuart

[Stuart Smith 5Participant @stuartsmith5]

[duncan webster 1Participant @duncanwebster1]

Read the 4qd documentation, this covers motors in series and why it isn’t a good idea

[duncan webster 1]

On duncan webster 1 Said:

Read the 4qd documentation, this covers motors in series and why it isn’t a good idea

Though it is allowed.

This is the parallel circuit.

I’m wondering if there’s more to Michael’s question than series vs parallel?   Stuart and I both provide circuits that omit practical details, like suppression capacitors and twisting the wires together.   Also, my circuit implies the motors are connected to a bus, when it’s more likely the circuit would be implemented by wiring each motor separately back to the controller.

A problem with the forum is that it’s not always obvious where the questioner is coming from.   This one could be:

• Michael’s first foray into electric motors and he’s not familiar with circuits or any of the theory.  Looking for simple advice.
• Michael is an experienced AC electrician who isn’t familiar with DC, batteries, and electronic controllers.  Looking for more advanced advice, best practice wiring, EMC etc.   Should he use a ring, what about fuses, why DC switching needs beefier hardware etc.?
• Michael is an Emeritus Professor of Electrical Engineering, who knows the theory inside out, but isn’t familiar with practical details.  In wiring the motors he’s encountered a strange “it doesn’t work” problem, and needs help on how to diagnose the problem.   Things like cables broken inside the insulation, loose terminals, corroded terminals, intermittently faulty controller, forgetting to set a safety interlock etc etc.

Michael: please ask again if we’ve jumped to a conclusion and answered the wrong question.

Dave

[duncan webster 1]

On duncan webster 1 Said:

Read the 4qd documentation, this covers motors in series and why it isn’t a good idea

Speaking only as a disinterested [but by no means uninterested] observer … I took Duncan’s hint and found the rabbit-hole:

https://www.4qdtec.com/

MichaelG.

.

https://www.4qd.co.uk/docs/motors-in-series-and-parallel/

[Robert Atkinson 2Participant @robertatkinson2]

Yes brushed DC motors generally don’t work well in series with voltage control unless well matched and with careful load sharing. Driving with controlled current works better as both (presumed identical and mechanically coupled) motors will develp the same torque.

Robert.

[Author]

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