DC Motor parameters

[Springles]

Hi:
Does anybody know how can I get the parameters of a DC motor, like J, B etc etc.???

Thanks

[RavensFan]

Does this have anything to do with LabVIEW?

What are J and B supposed to mean?

This sounds suspiciously like homework.

[Mathan]

Hai,

I googled ur query and came up with these params....

Viscous Friction (B)	0.008 Nms/rad
Shaft Inertia (J)	5.7e-7 kg m^2
Motor Constant (Km)	0.0134 Vs/rad
Armature Inductance (La)	6.5e-5 H
Armature Resistance (Ra)	1.9 ohm

Table 1. Initial Motor Parameter Values

see this and this....

Mathan

[CMal]

Springles,

A motor's parameters should be listed somewhere in the documenation (if there is any) that came with the motor.  Can you provide any information about the specific motor that you are working with?

Chris M

[Paul_m6]

I've never try this toolkit but it looks like is what you need:

http://sine.ni.com/nips/cds/view/p/lang/es/nid/13853 

I you dont want it then there are a lot of information about the recognition of the parameter of a DC motor on internet.

I did something when i was at the university 😃 i began by applying a constant voltage to the motor and measuring the variables ( current and velocity) in steady state, the derivates of the velocity and the current  in the differential equations of the model of the motor will be zero so u can have two first equation for the parameters of the motor. I found the resistance value by applying a LOW voltage with the rotor static and measuring the current. Then I applied a low sinosoidal voltage to the motor with a resistor of a known value in serial, with the rotor static, I measured the phase of the voltage in the resistor (the phase of the current) and the phase of the voltage applied, with this diference i found a relation between the Ra and L parameters ( resistance and inductance), and then L.  I dont remember now what else i did but i drove the system to some states that vanish some of the variables in the equations of the motor model to find another relations until I had the enough equations to resolve the system, the parameters i found was probably not too accurate but enough for modeling the plant.  I guess the usual way to find the parameters is by the step response, there are some theoretical ways to find the model of a plant, but i dont know them well. Anyway I think the best place to find this information is in the internet not in this forums because this forum is about labview and national instrument products.

I hope this information helps you a bit.