Symbol Reference

[mondo8205]

In the wiring diagram below what does the circled symbol mean and what is it doing? Im guessing the square with all the little circles is just a serial connection of some sort too.
View attachment 64439

 

[Grossel]

Hi.

As the legend on the right side says, it is a DC motor. A little more advanced version with separate connectors for stator windings and rotor windings. In adition I guess it have a tachometer output too, those connectors marked "RGB".

 

[mondo8205]

I know its a DC motor but what does the coil on top mean, stator windings or rotor windings, and what does it do?

 

[Reloadron]

My take is the coil on top is the field winding labeled F1 and F2. The armature is labeled A1 and A2 and the armature is drawn as rotating with the field being fixed. That is how I see it anyway.

Ron

 

[MrAl]

Hi Ron,

I agree, field winding F1 and F2 and armature winding A1 an and A2. It also appears that A1 is being used as the positive terminal.

I also agree that the tachometer output is RGB for red green black. Maybe red is positive bliack is ground and green is signal but that's just a guess as it could be black is ground and red and green are both signals that can indicate speed as well as direction even though the direction in this app appears to be fixed.

 

[mondo8205]

Just to let you guys know, its an electric golf cart im working on

 

[Reloadron]

So what does it do or not do? Since there is a diode across the armature I would guess the MOSFET block functions as maybe an H Bridge to reverse the field winding for motor direction. Note the armature does not go through the blocks with circles which I am guessing to be a large connector of sorts, maybe a large nylon connector? The MOSFET board assembly and Control Board assembly are in their own dashed line box which could mean they are away from the other parts. Much like the transceiver assembly which shows another connector. The throttle position sensor is a 5 K pot that likely is a TPS (Throttle Position Sensor). I am guessing here and may be totally wrong but if I had to guess sans seeing the thing in front of me that would be my guess. Again, what is the problem with the golf cart?

Ron

 

[mondo8205]

Well the cart just doesn't run. I think the controller is putting out a PWM signal to the motor to vary the speed. I just want to know what I should see if I use an oscilliscope and where this PWM signal(if thats what it is doing) is being applied F1,F2,A1,A2. I want to test if the controller is bad or the motor. So the next question is where would I apply the 48Vdc to test if the motor is fine.

The controller and motor are about the same price which is kinda expensive and I would like to know either or before I buy anything. The batteries are fine be the way.

 

[ronv]

A1, A2 is the armature and gets the PWM. I would ohm this out - probably in the range of .5 to 1 ohm.
F1, F2 is the field winding and acts like the magnets in a permanent magnet motor. It will be a few ohms.
It's hard to say what the field voltage will be. Some cars vary the field to extend the speed range. But it should not be zero. The armature gets the PWM so should vary from 0 to 48. I wouldn't try hooking the battery directly to the motor, but if you do both field and armature need voltage. You could probably hook them in Parallel for a short test.

 

[MrAl]

Hi,

If you apply a DC current to the field winding and turn the motor shaft it should generate some power at A1 and A2 as it should act as a generator if it is working. Might have to remove the motor though (and connections) and use a drill to turn the shaft. If you can light a small light bulb with it (maybe a 12v bulb) then it should be working ok. That would leave the controller.
I think you would want to try testing some of the other parts too though like that diode for example.

 

[Reloadron]

I assume #9 is working and when the cart is On that you have +Batt voltage on the A1 terminal with respect to ground?

Ron

 

[mondo8205]

Ok I got the cart going!

So, the armature voltage ranges from 0-48V as you vary the accelerator pedal. You want to go full speed its at 48V you want to go half the armature voltage is at 24V...etc.

The field windings voltage range from 0-20V. With an increase of load or when acceleration is needed the field windings are at 20V but when desired speed is achieved or max speed is achieved the field windings voltage is 0V.

My question:
At max speed with 48V on armature and 0V on the field windings can I apply a voltage on the field windings to increase the max speed? Can I run the motor at 48V on arm and a set voltage(EX 12V) constantly(increasing the max speed) and then the motor will stop accelerating when it reaches a point? What would be the steps to find out what I can make the motor do without burning it up?

Thanks guys

 

[mondo8205]

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