BS2 & with 24VDC brushless DC motor w/controller
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I have BOE with BS2 and want to use COUNT command to get tach info from a
Premotec Brushless DC motor with built in controller.
Here is the motor wiring info:
Red: +24
Black: Ground
White: Vin 0-5VDC for speed control
Green: Tacho, 36 pulses per revolution
Brown: F/R
I do not have a suitable clean power supply for this motor so I am using a
7amp variac (autotransformer) and a bridge rectifier to get my 24VDC for the
Red +24 and Black ground. I had was going to use the Vdd on the BOE to get
5VDC for the White wire and then connect the Vss to the Black ground going
into motor, assuming this would provide 5VDC to operate motor at full speed,
3500 RPM.
I was surpised that when my motor was hooked up to the 24VDC and I
connected only the White tach wire to the Vdd when the motor started at full
speed. There was only the one wire connecting the BOE. How can this work
with a circuit that is incomplete?
I did not connect the Green Tacho to the input because I do not know if it
is safe to connect the Vss to the Black Ground that goes back to the 24VDC
supply.
When running motor at full speed, I found that I got 2.6VDC from the Tacho
to ground.
Question - can I connect the BOE Vss to the Black ground off of the 24VDC
supply?
should the Tacho wire go through a resistor before going into pin?
Ken
Premotec Brushless DC motor with built in controller.
Here is the motor wiring info:
Red: +24
Black: Ground
White: Vin 0-5VDC for speed control
Green: Tacho, 36 pulses per revolution
Brown: F/R
I do not have a suitable clean power supply for this motor so I am using a
7amp variac (autotransformer) and a bridge rectifier to get my 24VDC for the
Red +24 and Black ground. I had was going to use the Vdd on the BOE to get
5VDC for the White wire and then connect the Vss to the Black ground going
into motor, assuming this would provide 5VDC to operate motor at full speed,
3500 RPM.
I was surpised that when my motor was hooked up to the 24VDC and I
connected only the White tach wire to the Vdd when the motor started at full
speed. There was only the one wire connecting the BOE. How can this work
with a circuit that is incomplete?
I did not connect the Green Tacho to the input because I do not know if it
is safe to connect the Vss to the Black Ground that goes back to the 24VDC
supply.
When running motor at full speed, I found that I got 2.6VDC from the Tacho
to ground.
Question - can I connect the BOE Vss to the Black ground off of the 24VDC
supply?
should the Tacho wire go through a resistor before going into pin?
Ken
Comments
I'm not sure I understand your setup, but here is a guess; If you are using
a variac plugged directly into line voltage, you have the potential to make
a lot of smoke, and receive a bad shock as well. One side of the line is
grounded, which may be completing your "incomplete circuit". The variac
should be connected to line through an isolation transformer, or else
replace it with a 24 volt transformer, which may be available as a surplus
item. It is always a good idea to use a resistor when interfacing to the
stamp; 1K to 10 K should work.
Good luck,
Ray McArthur
Original Message
From: Ken Agee <kenagee@a...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, January 02, 2002 1:52 AM
Subject: [noparse][[/noparse]basicstamps] BS2 & with 24VDC brushless DC motor w/controller
> I have BOE with BS2 and want to use COUNT command to get tach info from a
> Premotec Brushless DC motor with built in controller.
> Here is the motor wiring info:
> Red: +24
> Black: Ground
> White: Vin 0-5VDC for speed control
> Green: Tacho, 36 pulses per revolution
> Brown: F/R
>
> I do not have a suitable clean power supply for this motor so I am using a
> 7amp variac (autotransformer) and a bridge rectifier to get my 24VDC for
the
> Red +24 and Black ground. I had was going to use the Vdd on the BOE to get
> 5VDC for the White wire and then connect the Vss to the Black ground going
> into motor, assuming this would provide 5VDC to operate motor at full
speed,
> 3500 RPM.
>
> I was surpised that when my motor was hooked up to the 24VDC and I
> connected only the White tach wire to the Vdd when the motor started at
full
> speed. There was only the one wire connecting the BOE. How can this work
> with a circuit that is incomplete?
>
> I did not connect the Green Tacho to the input because I do not know if it
> is safe to connect the Vss to the Black Ground that goes back to the 24VDC
> supply.
>
> When running motor at full speed, I found that I got 2.6VDC from the Tacho
> to ground.
>
> Question - can I connect the BOE Vss to the Black ground off of the 24VDC
> supply?
> should the Tacho wire go through a resistor before going into pin?