A motor has an armature resistance of 4 ohm. On a 240 V supply and a light load, the motor speed is 200 rpm and the armature current is 5 A Calculate the motor speed at a full load. When armature current is 20 A.

Explanation

To solve the problem step by step, we will use the relationship between the back EMF (Electromotive Force), armature current, armature resistance, and motor speed.

### Step 1: Calculate the Back EMF at Light Load
Given:
- Supply Voltage (V) = 240 V
- Armature Resistance (R) = 4 Ω
- Armature Current (I1) = 5 A

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