Experiments In Machines Lab No Load Tests On A Dc Shunt Motor (swinbourns Test)
Objective:to determine the performance of the given dc shunt machine in both generator and motor modes of operation
Swinburn’s test is a no-load test on a dc machine. The machine is started and run as a dc motor with shaft decoupled from any load. In this regard the test is very easy to carry out for a machine of any size, particularly convenient for a large machine.
the input to motor at no-load comprises of:
iron losses (pi)
Mechanical, friction and windage loss (pwf)
Field copper loss (pshf)
Armature copper loss
(Armature resistance is measured by drop test and corrected to operating temperature of about 750c)
stray load losses are estimated to be 1% of kw rating of the machine at full – load and considered proportional to square of armature current.
with the above data the machine performance at any load (or a set of loads) can be predetermined either as motor or generator.
Equipment required: all the measuring instruments associated with each experiment are industrial grade. These instruments are housed in an elegant cabinet as a package. Range of instruments and accessories (standard format)
1. 2hp dc motor 220v 2hp 1500rpm with standard screen protected/drip proof (ip21)
2. 3-4 point dc starters with protectors.
3. Suitable digital voltmeter dc to measure voltage across armature
4. Suitable digital ammeter dc to measure filed current.
5. Suitable digital ammeter dc to measure armature current.
6. Suitable digital tachometer to read rpm of the motor.
7. Suitable rheostat for armature circuit.
8. Suitable rheostat for field circuit.
9. Rectifier unit 0-240v dc @ 1. 5kva with power failure protection.