1 Topic by bbriggsgeek

  • bbriggsgeek
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Topic: Power drops dramatically when switch on motor

I let everything heat up as instructed.  When I switch the motor on, the temperature on the PID drops dramatically, about 50 degrees in a few seconds.  The motor sounds like it's really straining and the stall protection board's red light sometimes come on.  If I leave it on, the motor sometimes just winds down and quits.

2 Reply by bbriggsgeek

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Re: Power drops dramatically when switch on motor

I let everything heat up as instructed.  When I switch the motor on, the temperature on the PID drops dramatically, about 50 degrees in a few seconds.  The motor sounds like it's really straining and the stall protection board's red light sometimes come on.  If I leave it on, the motor sometimes just winds down and quits.

3 Reply by os3dp (edited by os3dp 2016-08-20 19:47:51)

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Re: Power drops dramatically when switch on motor

Can you measure the voltage coming out of the power supply before and while it has troubles?

-os3dp

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4 Reply by os3dp

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Re: Power drops dramatically when switch on motor

I should probably elaborate on my theory.  If the power supply is having troubles, then the voltage would tend to drop.  I'm sure there could be other reasons the voltage would drop, but that is my first idea. 

Another thought would be to check that the thermocouple is secure.  If the motor turns on and it moves the thermocouple then it would register quite quickly.

-os3dp

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5 Reply by elmoret

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Re: Power drops dramatically when switch on motor

I don't think this is a case of the motor, but rather the fan which is cooling the nozzle - the PID isn't responding fast enough.

Things to do:

1.) PID tune the controller
2.) Block the fan partly and unblock it over a few minutes so the controller can keep up
3.) Wire the fan instead to the main switch (but this will make heatup slower).

Please also measure the power supply voltage, under load at the inputs to the stall protection board.

I'm also merging the two threads.

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6 Reply by bbriggsgeek

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Re: Power drops dramatically when switch on motor

Voltage on wire, right off the power supply is about 12.33v both with and without load.
Voltage at the input of the stall board is 12.15v.

I did the autotune on the PID controller.
I took the fan off the nozzle and let it heat some more.  The temperature didn't drop when I turned on.  I'll try hooking the nozzle fan up to the main switch.

7 Reply by elmoret

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Re: Power drops dramatically when switch on motor

Nice, then the power supply is solid and it sounds like the temperature was just dropping due to the sudden change of the fan coming on. The 3 suggestions above should help with that.

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