What are the symbols in these electric motor equations?

[CraigH]

I'm revising for an exam and i’ve come across these equations in my lecture notes.
Has anyone seen these equations before, and can tell me what the symbols represent?

T = k1 ᶲ Ia

Ea = k1ᶲ2πN = k2ᶲN

Ea = Va-IaRa

N = (Va-IaRa) / (2πk1ᶲ)

Im guessing T is torque, Ea is the volatge across the motor, and Va is the source voltage. I am not sure though.

Thanks

Edit:

The π symbol is pi

 

[SirAskalot]

T is torque.
Ea is internal EMF
Va is terminal voltage
Ia is armature current
N is rotor speed (probably in rpm)
Uppercases Phi Φ is flux due to field current.
k1 is a constant

 

[CraigH]

Thanks, can i just ask, what do you mean by armature current? Is this just the current through the motor? Also what do you mean by internal EMF?

 

[SirAskalot]

Yes, its "just" the current through the motor. More specific, the current through the armature winding. Internal EMF is the electromotive force due to rotating magnetic field, faradays law etc...

Formulas do you no good if you don't know the basis and derivation of them. I would suggest reading the course book in order to get the basic understanding of electromagnetism and DC motors.

 

[alphysicist]

, which is a mathematical constant. The other symbols represent physical quantities in the equations:

T = torque (measured in newton-meters or Nm)
k1 = a constant specific to the motor design
ᶲ = magnetic flux
Ia = armature current (measured in amperes or A)
Ea = back electromotive force (EMF) or voltage (measured in volts or V)
N = rotational speed (measured in revolutions per minute or rpm)
k2 = another constant specific to the motor design
Ra = armature resistance (measured in ohms or Ω)
Va = applied voltage (measured in volts or V)

Overall, these equations describe the relationship between torque, speed, and voltage in an electric motor, and the role of armature current and resistance in producing torque and back EMF.