Control_secvor

[TrinhAnhMinh]

help me!
The information on the motor is as follows:
Model Number E543
Serial Number G056926
Date Code 0893
Part Number 0547-01-009
Customer Part Number 40271-146-01
Could you give me some more information about this?
kt Torque constant?
Ke Voltage Constant?
Winding resistance (OHM) RA ?
Max pulse current (A)?
Armature Induct. (mH)?

TrinhAnhMinh

[Al_The_Man]

I have Older Electro-craft catalogues but they only show up to E542.
This is some notes I put together when I was looking for similar information and found them in various sources:
A simplified model of a DC motor can be derived assuming the armature inductance to be zero and ignoring the resonance effect.
With these stipulations the equations are:

1. V=Ia R + Ke omega (Ia=armature current, R=armature resistance,
Ke=electr. constant, omega=speed)

2. Tg=Kt Ia (Tg=costant, Kt=torque constant)

3. Tg=J d(omega)/dt (J=inertia, d(omega)/dt=accel.)

The DC motor transfer function is:
Gm(s)=(1/Ke)/(1+s(Rj/KtKe)), which can be written Gm(s)=(1/Ke)/(1+sTm)
where Tm=mechanical time constant.
To measure the parameters you are asking for, use the following:

A. Measure the armature resistance as below, then apply voltage to the motor without load and measure the current and speed. From equation 1. you can easily derive Ke.

B. Apply nominal current to the motor (with the shaft locked) by means
of a variable voltage source. Measure the torque on the shaft. From this you can derive the torque constant Kt=Torque/Amp.

C. You will find that Kt is approx. equal to Ke

D. For the inertia you can obtain it by calculation from the size and
material of the rotor.

Note 1: inductance can be ignored- the electrical time constant is
very short compared to the mech time constant so that it can usually be
ignored.
You can measure the mech time constant by running the motor up to speed at no load, disconnecting the supply and letting it coast down- plot speed vs time and fit to exponential N=No(e^-t/Tm) time to drop to 36.8% of original speed is the time constant.

Note2: If it is a permanent magnet motor, you can determine the internal emf by spinning it at rated speed and measuring the open circuit voltage. The voltage at any other speed will be directly proportional to speed. To measure the winding resistance, lock the rotor so it doesn't turn and measure the current with a small measured voltage applied (so as not to exceed rated current) Don't not use a multimeter's ohm range.
If you want to find the inductance, you should use a scope- apply a voltage, rotor locked and look at the current trace vs time.
This will be of the form i=K[1-e^Rt/L] where i is the current at time t.
In most cases the inductance can be ignored as its effects are generally swamped by the mechanical inertia in transient cases and is of little importance for steady state.
Al.

[gotis]

Any help for me to?

Have a Baldor BSM3R 3phase dc servo motor but no driver, anyone know of any cheap 3phase drivers?

1,26Kw 130 volts 133Hz 5,6A 4000rpm

[Al_The_Man]

I assume you mean DC brushless? If I can't get on ebay, I use Copley Controls or A-M-C they have some that should do the trick, but you did not mention what method of control you need, analogue or step/dir.
Al.

[gotis]

Yes it is brushless with permanentmagnets and a resolver.
I was hoping to use it as a spindlemotor so step/dir would be perfect but analogue is acceptable as well, I´ll be using mach3.

I have the driver for it but it was rackmounted and the rack is scrapped, no way of knowing how to hook it up, I´m a total newbie on this level of electronics.

[unterhaus]

I don't think cheap and resolver go together in the same sentence. They seem to be pretty much obsolete in new equipment, so you either have to figure out what's in the rack, or go on ebay and potentially waste a lot of money. My collection of mismatched amps and motors is pretty impressive.