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From: Jerome on 10 Feb 2010 04:14
Hi All,
I'm currently simulating a hydraulic system.
I'm driving my pump with the speed from a asynchronous motor (simpowersystems library). The speed output from the motor is connected to ideal velocity source which is connected to the pump. To feed the motor with torque, i want to measure with a torque sensor the torque between the velocity source and the pump shaft and feed it back.

The issue is that the torque measured is to high and the output data (power measurement of the motor) wrong, compared to when I run the motor in speed mode, an drive the pump with the delivered torque from the motor, an measure the speed between the torque source and the pump shaft and feed it back to the motor, which gives me propper results.
This also applies if i run both, motor and pump with torque and if i run both with speed.
I want to run my motor with torque though, because i cannot neglect its inertia.

Sensors and Sources are in both cases connected the C port is connected to mechanical rotational reference.

Hope you understand the problem
Cheers,

Jerome
From: Arnaud Miege on 11 Feb 2010 09:01
"Jerome " <j.steg(a)gmx.net> wrote in message <hkttcs$3pj$1(a)fred.mathworks.com>...
> Hi All,
> I'm currently simulating a hydraulic system.
> I'm driving my pump with the speed from a asynchronous motor (simpowersystems library). The speed output from the motor is connected to ideal velocity source which is connected to the pump. To feed the motor with torque, i want to measure with a torque sensor the torque between the velocity source and the pump shaft and feed it back.
>
> The issue is that the torque measured is to high and the output data (power measurement of the motor) wrong, compared to when I run the motor in speed mode, an drive the pump with the delivered torque from the motor, an measure the speed between the torque source and the pump shaft and feed it back to the motor, which gives me propper results.
> This also applies if i run both, motor and pump with torque and if i run both with speed.
> I want to run my motor with torque though, because i cannot neglect its inertia.
>
> Sensors and Sources are in both cases connected the C port is connected to mechanical rotational reference.
>
> Hope you understand the problem
> Cheers,
>
> Jerome

Torque is through variable that needs to be measured in series, whereas speed is an across variable that needs to be measured in parallel. Have a look at the following thread:
http://www.mathworks.com/matlabcentral/newsreader/view_thread/270563

Could your problem be that you are not measuring torque correctly?

HTH,

Arnaud
From: Jerome on 12 Feb 2010 05:21
"Arnaud Miege" <arnaud.miege(a)nospam.mathworks.co.uk> wrote in message <hl12j0$6dv$1(a)fred.mathworks.com>...
> "Jerome " <j.steg(a)gmx.net> wrote in message <hkttcs$3pj$1(a)fred.mathworks.com>...
> > Hi All,
> > I'm currently simulating a hydraulic system.
> > I'm driving my pump with the speed from a asynchronous motor (simpowersystems library). The speed output from the motor is connected to ideal velocity source which is connected to the pump. To feed the motor with torque, i want to measure with a torque sensor the torque between the velocity source and the pump shaft and feed it back.
> >
> > The issue is that the torque measured is to high and the output data (power measurement of the motor) wrong, compared to when I run the motor in speed mode, an drive the pump with the delivered torque from the motor, an measure the speed between the torque source and the pump shaft and feed it back to the motor, which gives me propper results.
> > This also applies if i run both, motor and pump with torque and if i run both with speed.
> > I want to run my motor with torque though, because i cannot neglect its inertia.
> >
> > Sensors and Sources are in both cases connected the C port is connected to mechanical rotational reference.
> >
> > Hope you understand the problem
> > Cheers,
> >
> > Jerome
>
> Torque is through variable that needs to be measured in series, whereas speed is an across variable that needs to be measured in parallel. Have a look at the following thread:
> http://www.mathworks.com/matlabcentral/newsreader/view_thread/270563
>
> Could your problem be that you are not measuring torque correctly?
>
> HTH,
>
> Arnaud
Hi Arnaud,
thx for your response.
I read that threat before I tried to do the measurements. The measurement do work actually, but the output is wrong and the dynamic of the motor changes as well.
I'm also encoutering this problem when I run the motor with the SimElectronics induction drive. I connect the R port to the pumps shaft, and the C port to the C port of the rotational torque measurement tool. The dynamic of the motor changes aswell in this case.
Cheers,
Jerome
From: Arnaud Miege on 12 Feb 2010 05:44
"Jerome " <j.steg(a)gmx.net> wrote in message

> Hi Arnaud,
> thx for your response.
> I read that threat before I tried to do the measurements. The measurement do work actually, but the output is wrong and the dynamic of the motor changes as well.
> I'm also encoutering this problem when I run the motor with the SimElectronics induction drive. I connect the R port to the pumps shaft, and the C port to the C port of the rotational torque measurement tool. The dynamic of the motor changes aswell in this case.
> Cheers,
> Jerome

Can you upload your model or at least a screenshot of it to a filesharing site, so that we can have a look?

Thanks,

Arnaud
From: Jerome on 14 Feb 2010 18:11
"Arnaud Miege" <arnaud.miege(a)nospam.mathworks.co.uk> wrote in message <hl3bdl$7s2$1(a)fred.mathworks.com>...
> "Jerome " <j.steg(a)gmx.net> wrote in message
>
> > Hi Arnaud,
> > thx for your response.
> > I read that threat before I tried to do the measurements. The measurement do work actually, but the output is wrong and the dynamic of the motor changes as well.
> > I'm also encoutering this problem when I run the motor with the SimElectronics induction drive. I connect the R port to the pumps shaft, and the C port to the C port of the rotational torque measurement tool. The dynamic of the motor changes aswell in this case.
> > Cheers,
> > Jerome
>
> Can you upload your model or at least a screenshot of it to a filesharing site, so that we can have a look?
>
> Thanks,
>
Hi Arnaud,
i just uploaded them
thx
> Arnaud
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