Dynomotion

Group: DynoMotion Message: 6121 From: daveymahomh600e Date: 11/19/2012
Subject: Axis Travel Direction
Hello Folks,

I know this question will make you people that understand this stuff cringe, but here goes anyway...

In the simple world where I live (most of the time) to reverse the direction of a 3 phase motor you switch two of the three power leads to the windings. I believe servos are different. How do I change the positive direction of my 3 phase brushless servo motors? I experimented with the input gain, output gain, input and output gain, but that didn't seem to work.

Thanks,
David.
Group: DynoMotion Message: 6122 From: bennyattwell Date: 11/19/2012
Subject: Re: Axis Travel Direction
most servo drives ive used have a fwd run and reverse run input one of which must be on to drive the servo. if you swap the input the servo will be reversed. eg. if your using forward your servo will run clockwise for a forward command. if you use the reverse input the servo will run anti clockwise for a foreward command.

if this doesnt help give me the model of servo drive and il check it out.

--- In DynoMotion@yahoogroups.com, "daveymahomh600e" <david.m.stevenson@...> wrote:
>
> Hello Folks,
>
> I know this question will make you people that understand this stuff cringe, but here goes anyway...
>
> In the simple world where I live (most of the time) to reverse the direction of a 3 phase motor you switch two of the three power leads to the windings. I believe servos are different. How do I change the positive direction of my 3 phase brushless servo motors? I experimented with the input gain, output gain, input and output gain, but that didn't seem to work.
>
> Thanks,
> David.
>
Group: DynoMotion Message: 6123 From: bennyattwell Date: 11/19/2012
Subject: Re: Axis Travel Direction
oops. sorry, thought i was replying to someone in the normal mach3 forum. il keep my mouth shut. (i monitor too many forums)

--- In DynoMotion@yahoogroups.com, "bennyattwell" <brendon@...> wrote:
>
> most servo drives ive used have a fwd run and reverse run input one of which must be on to drive the servo. if you swap the input the servo will be reversed. eg. if your using forward your servo will run clockwise for a forward command. if you use the reverse input the servo will run anti clockwise for a foreward command.
>
> if this doesnt help give me the model of servo drive and il check it out.
>
> --- In DynoMotion@yahoogroups.com, "daveymahomh600e" <david.m.stevenson@> wrote:
> >
> > Hello Folks,
> >
> > I know this question will make you people that understand this stuff cringe, but here goes anyway...
> >
> > In the simple world where I live (most of the time) to reverse the direction of a 3 phase motor you switch two of the three power leads to the windings. I believe servos are different. How do I change the positive direction of my 3 phase brushless servo motors? I experimented with the input gain, output gain, input and output gain, but that didn't seem to work.
> >
> > Thanks,
> > David.
> >
>
Group: DynoMotion Message: 6124 From: daveymahomh600e Date: 11/19/2012
Subject: Re: Axis Travel Direction
Very interesting.

In my case, I am using a SnapAmp as the drive, so I suspect there is a setting within the SnapAmp which would control this. I'll have a look at that.

The motor is a Baldor BSM80C-375, if that makes a difference.

Thanks,
David.

--- In DynoMotion@yahoogroups.com, "bennyattwell" <brendon@...> wrote:
>
> most servo drives ive used have a fwd run and reverse run input one of which must be on to drive the servo. if you swap the input the servo will be reversed. eg. if your using forward your servo will run clockwise for a forward command. if you use the reverse input the servo will run anti clockwise for a foreward command.
>
> if this doesnt help give me the model of servo drive and il check it out.
>
> --- In DynoMotion@yahoogroups.com, "daveymahomh600e" <david.m.stevenson@> wrote:
> >
> > Hello Folks,
> >
> > I know this question will make you people that understand this stuff cringe, but here goes anyway...
> >
> > In the simple world where I live (most of the time) to reverse the direction of a 3 phase motor you switch two of the three power leads to the windings. I believe servos are different. How do I change the positive direction of my 3 phase brushless servo motors? I experimented with the input gain, output gain, input and output gain, but that didn't seem to work.
> >
> > Thanks,
> > David.
> >
>
Group: DynoMotion Message: 6125 From: Tom Kerekes Date: 11/19/2012
Subject: Re: Axis Travel Direction
Hi David,

With any working Servo to reverse the direction two things must be reversed otherwise there will be positive instead of negative feedback (runaway servo).

You can reverse the encoder input by reversing the InputGain0 parameter.

You can reverse the output torque by shifting the commutation by 1/2 cycle (180 degree phase shift is the same as multiplying by -1).  Or just run the AutoPhaseFind.c again with the reversed input and it will compute the appropriate commutation offset.

HTH
Regards
TK


Group: DynoMotion Message: 6126 From: daveymahomh600e Date: 11/19/2012
Subject: Re: Axis Travel Direction
Hi Tom,

How do I shift the commutation by 1/2 cycle?

Thank you,
David.

--- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@...> wrote:
>
> Hi David,
>
> With any working Servo to reverse the direction two things must be reversed otherwise there will be positive instead of negative feedback (runaway servo).
>
> You can reverse the encoder input by reversing the InputGain0 parameter.
>
> You can reverse the output torque by shifting the commutation by 1/2 cycle (180 degree phase shift is the same as multiplying by -1).  Or just run the AutoPhaseFind.c again with the reversed input and it will compute the appropriate commutation offset.
>
> HTH
> Regards
> TK
>
>
>
>
> ________________________________
> From: daveymahomh600e <david.m.stevenson@...>
> To: DynoMotion@yahoogroups.com
> Sent: Monday, November 19, 2012 10:15 AM
> Subject: [DynoMotion] Axis Travel Direction
>
>
>  
> Hello Folks,
>
> I know this question will make you people that understand this stuff cringe, but here goes anyway...
>
> In the simple world where I live (most of the time) to reverse the direction of a 3 phase motor you switch two of the three power leads to the windings. I believe servos are different. How do I change the positive direction of my 3 phase brushless servo motors? I experimented with the input gain, output gain, input and output gain, but that didn't seem to work.
>
> Thanks,
> David.
>
Group: DynoMotion Message: 6127 From: Tom Kerekes Date: 11/19/2012
Subject: Re: Axis Travel Direction
Hi David,

Add (or subtract) 1/2 the number of encoder counts per cycle to the commutation offset.

Regards
TK


Group: DynoMotion Message: 6128 From: daveymahomh600e Date: 11/19/2012
Subject: Re: Axis Travel Direction
Hi Tom,

Well, that certainly makes sense. :)

Thank you,
David.

--- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@...> wrote:
>
> Hi David,
>
> Add (or subtract) 1/2 the number of encoder counts per cycle to the commutation offset.
>
> Regards
> TK
>
>
>
>
> ________________________________
> From: daveymahomh600e <david.m.stevenson@...>
> To: DynoMotion@yahoogroups.com
> Sent: Monday, November 19, 2012 1:52 PM
> Subject: [DynoMotion] Re: Axis Travel Direction
>
>
>  
> Hi Tom,
>
> How do I shift the commutation by 1/2 cycle?
>
> Thank you,
> David.
>
> --- In DynoMotion@yahoogroups.com, Tom Kerekes <tk@> wrote:
> >
> > Hi David,
> >
> > With any working Servo to reverse the direction two things must be reversed otherwise there will be positive instead of negative feedback (runaway servo).
> >
> > You can reverse the encoder input by reversing the InputGain0 parameter.
> >
> > You can reverse the output torque by shifting the commutation by 1/2 cycle (180 degree phase shift is the same as multiplying by -1).  Or just run the AutoPhaseFind.c again with the reversed input and it will compute the appropriate commutation offset.
> >
> > HTH
> > Regards
> > TK
> >
> >
> >
> >
> > ________________________________
> > From: daveymahomh600e <david.m.stevenson@>
> > To: DynoMotion@yahoogroups.com
> > Sent: Monday, November 19, 2012 10:15 AM
> > Subject: [DynoMotion] Axis Travel Direction
> >
> >
> >  
> > Hello Folks,
> >
> > I know this question will make you people that understand this stuff cringe, but here goes anyway...
> >
> > In the simple world where I live (most of the time) to reverse the direction of a 3 phase motor you switch two of the three power leads to the windings. I believe servos are different. How do I change the positive direction of my 3 phase brushless servo motors? I experimented with the input gain, output gain, input and output gain, but that didn't seem to work.
> >
> > Thanks,
> > David.
> >
>