Not Sure if I need SPDT switch

I have 2 separate powers sources, #1 source is (2) Batteries in Parallel, #2 source is an Alternator connected to a rectifier. I believe I would need a SPDT on/off/on connected to power a BLDC motor through a BLDC motor controller driver but only 1 source at a time. Batteries would Start it, then I switch to the Alternator.
However, all the sites shows 1 power source going to 2 different circuits, NOT 2 different power sources going to 1 circuit one at a time.
Also, there is a difference in Wattage, so I didn't know If I would need a Special kind of switch. Max 24A@36vDC, and max 30A@12vDC.

Rather puzzled by the three green wires going to the right hand side of the motor. What are they for?

I just forgot to color match it.

Correction, I misread. Motor is wye wound and that is the Ground wires.

A BLDC motor does not have ground wires!


BLDC motors are DELTA wound.

Please before doing anymore, Google

bldc and esc tutorial

And read/view some tutrorials.

Tom... :smiley: :+1: :coffee: :australia:

The contacts of your switch need to be able to handle the max current; the insulation neeeds to be able to handle the max voltage - even when its hot.

Provide links to those parts?

No, wye and delta are both used, depending. It makes no difference to the electronics, you just need to know the motor constant and its limits, and how the windings are configured affects where you need to place any Hall sensors.

Perhaps a link to the datasheet for the particular motor involved would be wise? Ditto every piece of hardware you mention.

You can message me on Facebook messenger, Jon Alan Stephens, Jon Alan Stephens

I designed the Stator, and would be the one winding it. I am more familiar with Wye windings than Star.

the BLCD control is sensorless, has 3 wires for the potentiometer, 2 wires for DC source input, and 3 wires that go to the motor stator windings. since its not in Star/Delta woundings, its in Wye woundings, I would need to ground it, correct??

So I would need a SpDt switch that can handle 36v Dc? I am not finding ANY, lol thats a problem, right? How close do I need to get to be in tolerance? 28Vdc or closer? Would this be better that SPDT ??


You clearly do not understand how BLDC motors operate. :worried:

Which is most curious if:


There are two common electrical winding configurations; the delta configuration connects three windings to each other in a triangle-like circuit, and power is applied at each of the connections. The wye (Y-shaped) configuration, sometimes called a star winding, connects all of the windings to a central point, and power is applied to the remaining end of each winding.

Guess what - wikipedia!

That switch look s suitable but you would need to disable the 1&2 position.

No, you leave the common connection unconnected in a wye motor driven by this controller else you'll explode it.

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