To determine the efficiency of 3- ɸ induction motor by performing load test. To obtain the performance curves for the same.
S.no | Equipment | Type | Range | Quantity |
1 | Voltmeter | MI | (0-600)V | 1nos |
2 | Ammeter | MI | (0-10)A | 1nos |
3 | Wattmeter | Electro dynamo meter type | 10A/600V UPF/10A/600V LPF | 1no |
4 | Techometer | Digital | (0-9999)RPM | 1nos |
5 | Connecting Wires | -- | ---- | Required |
Name plate details:-
Power rating : 5Hp
Voltage : 400V
Current : 6.8A
Speed (RPM) : 1450
Frequency : 50Hz
PF : Lagging
3- ɸ Auto transformer Details:
Input Voltage: _____415_____________ (Volt)
Output Voltage: ___0-470_____________ (Volt)
Current:__________________ (Amp)
Freq.:_____________50Hz______________(Hz)
Circuit Diagram:
Tabular column:
S.no | Voltage(V) | NO.Volt age( V) Curre nt(A) | Wattmeter reading/W1+/W2 | I/P Poqwe /W1+ /W2(W) | Spring Balance kg/S1/S1-S2 | Speed (N) rpm | % Slip | Power factor cosΦ= w1+w2 /√3vi | Torque (Nm) | Pout(W) | %η |
1 | 400 | 1.2 | 240/240 | 280 | 0/0/0 | 1498 | 0.13 | 0.57 | 0 | 0 | 0 |
2 | 400 | 2.2 | 880/240 | 1160 | 1.5/6.5/5 | 1485 | 1 | 0.76 | 5.49 | 853.74 | 76.31 |
3 | 400 | 3 | 1120/480 | 1600 | 2.5/10/7.5 | 1454 | 3.6 | 0.76 | 8.24 | 1254.64 | 78.41 |
4 | 400 | 3.6 | 1440/640 | 2080 | 3.5/14/10.5 | 1424 | 5.06 | 0.83 | 11.53 | 1720.85 | 827.3 |
5 | 400 | 4 | 1600/720 | 2320 | 4.5/16.5/12 | 1398 | 6.8 | 0.83 | 13.18 | 1929.52 | 83.16 |
6 | 400 | 5 | 1960/880 | 2840 | 5.5/19/13.5 | 1382 | 7.8 | 0.81 | 14.83 | 2146.23 | 75.57 |
7 | 400 | 6 | 2000/960 | 2960 | 6.0/50/14 | 1268 | 7.54 | 0.7 | 15.38 | 2093.76 | 70.23 |
Model Calculation:
Input power drawn by the motor W = (W1 ± W2) watts
Shaft Torque, T sh= 9.81 (S1~ S2) R→N-m R → Radius of drum in meters
Output power in watts =2πNTsh/60 watts
1. efficiency = output power in watts /Input power in watts x 100
Calculations:
% Slip = (Ns-N)/Ns*100
=120f/P
Power factor of the induction motor cosϴ=W/√3 VLIL
Model Graphs:
Precautions:
Result:The load test on 3-Φ squirrel cage induction motor conducted and the characteristics of torque, speed, efficiency versus output power were drawn.
Via Questions:
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