Page 334 - CTS - Mechanic Diesel - TP

MECHANIC DIESEL - CITS

Fig 1

2 Select proper sizes of cables, fuse wires, switches etc., asper the name - plate ratings (rated capacity)of the
given 3-phase alternator
3 Connect the exciter output terminals to the field of the alternator with the rheostat, ammeter and voltmeter.
(Fig 1)
The exciter output voltage is shownin Fig1as 220V DC. Different manufacturers choose different exciter
voltages suitable for their alternators. You may have to select the voltmeter and ammeter ratings according to
the voltage rating of the field of the available alternator.
4 Connect the alternator terminals RYB and N to the load as per the circuit diagram (Fig 1). Keep the load
switches and also all the lamp switches of the lamp load in the `off’ position.
Check the voltage rating of the power factor and frequency meters whether they are for phase voltage
or line voltage. Connect accordingly. Don ot forget to connect the star point of the lamp load to the
neutral point of the alternator.The bulb watta gerating should be equal in all lamps.

5 Show the connection to your instructor and obtain his permission to start the prime mover.
6 Run the alternator at its rated speed. Measure and record the speed. Speed. r.p.m.
7 Build up its voltage by adjusting the field rheostat to the rated voltage of the alternator. Read and record it.
Voltage..................volts.

TASK 2: Loada 3-phase alternator with are sistive load
1 Close the T.P.I.C.switch of the lamp load and note down the values of the load current, (which will be zero), the
terminal voltage, P.F. and frequency in Table 2

Frequency
S. Loadcurrent equal in Terminal Power Power =
No. all the threephases I L Voltage VL kept Factor cos Ø L L Remarks
I cosØ
constant

317
CITS : Automotive - Mechanic Diesel - Exercise 18.4