# Induction motor

Discussion in 'Homework Help' started by cpleng7, Aug 15, 2010.

1. ### cpleng7 Thread Starter Active Member

Dec 18, 2008
120
0
Did anyone know how to calculate the maximum load that 4 hp class F induction motor can sustain?

2. ### cpleng7 Thread Starter Active Member

Dec 18, 2008
120
0
how to i know the induction motor is in full load condition

3. ### retched AAC Fanatic!

Dec 5, 2009
5,201
312
Well, most motors are rated with a "LRA" or Locked Rotor Amps number.

This number shows the amp draw when the motor just starts, or if the load caused the motor shaft to stop spinning.

4. ### sify87 New Member

Jun 23, 2010
9
0
Ok! First of all u cannot find a motor of 4HP.The Full Load Current of a 3HP motor is 4.8A and a 5HP motor is 7.8A.U jst use the simple formula
P(kw)=1.732 X V X I X pf X Efficiency.
So, for a 4HP motor(although u cannot find it) change the rating of motor from HP to watt,voltage-415V,pf-0.8,Eff-0.8(assuming) and u jst calculate it.Thanks!!

5. ### cpleng7 Thread Starter Active Member

Dec 18, 2008
120
0
if I add some weight to the shaft is that consider the load for the induction motor?

6. ### retched AAC Fanatic!

Dec 5, 2009
5,201
312
Yes. Any weight or force on the shaft is the "load".

7. ### sify87 New Member

Jun 23, 2010
9
0
Ok! how can u add some weight to the rotating shaft??
Basically the motor shaft is coupled to the pumps or conveyors or etc. Now when the motor is started then it is said that the motor is in load condition.In this condition two types of load acts on the motor shaft