Meaning of symbols in DC electric motor equations: T, k1, ᶲ, Ia, Ea, Va, Ra, N

Im 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. Im not sure though.

Thanks

These are equations for DC motors - usually based on the DC Shunt motor but can be applied to all types.

Ea is the voltage produced by the armature is oppostion to the applied voltage E (your Va) so re-writing your eq
Ea = E - (Ia* Ra) Ra is the armature resistance

N is speed in RPM

So N = 60*Ea / (Z*60) most assume that at rated load E and Ea are essentially the same but they are not as Ea and E can never but equal. Assuming they are though will give you the max speed possible with a given flux (k)

Z is a constant due to motor construction - active number of conductors in the armature - I like to call it the fudge factor

Torque is proportinal to flux and armature current

T=Z*K/ 6.28


in general
Torque goes up ( load increases) current goes up, speed goes down

If flux goes up - speed goes down

by the way Power P = Ea * Ia

which is also P= nT/ 9.55

Good book to look at for all these equations
Electrical Machines, Drives and Power Systems by Theodore Wildi

also google " DC motor equations"

here are few links to look at
http://zone.ni.com/devzone/cda/ph/p/id/46
http://coep.vlab.co.in/?sub=33&brch=95&sim=1040&cnt=1