COVER A 3K4335 - Caterpillar

Illustration 1. Connections for exciter reactor polarity test.2. Adjust the voltmeter to a 10 or 20 volt scale first. For some reactor windings, it will be necessary to use a lower voltage scale to get an indication.3. Look at the voltmeter and move the switch to the "ON" position. The desired indication is a positive (+) voltage on the digital multimeter, or a needle movement up the scale on a dial face voltmeter. The indication will be only temporary, and the meter will go back to zero.4. After two seconds or more, move the switch to the "OFF" position. The desired indication is a negative (-) voltage on the digital multimeter, or a needle movement down the scale (below the zero) on a dial face voltmeter. This indication, like the one in Step 3, will be only temporary, and the meter will go back to zero. Do not move the switch to either the "ON" or "OFF" position at intervals of less than two seconds minimum. Shorter intervals will not permit stability in the flow of current.5. Do Steps 3 and 4 again with the voltmeter connected to Y1 and Y2, then with the voltmeter connected to Z1 and Z2. This will make sure all the connections have the correct identification marks.If the polarity of the "H" winding is not known, it can be checked as follows: ... The single terminal on one side of the reactor is H1 and the two terminals on the opposite side are H2 and H3.... Connect a 115 Volt AC source to H1 and to either terminal on the opposite side (H2 or H3).... Check the voltage between the H1 terminal and the terminal on the opposite side which is not connected to the 115 Volt source (the third terminal).... If the voltage measures less than 115 Volts (approximately 105 Volts), the voltmeter is connected to H1 and H2, and the 115 Volt source is connected to H1 and H3.... If the voltage measures more than 115 Volts (approximately 126 Volts), the voltmeter is connected to H1 and H3, and the 115 Volt source is connected to H1 and H2.
This permits correct identification of the "H" winding terminals.
Exciter Reactor Winding Test
1. Connect a 115 Volt AC source and an AC voltmeter to the reactor as shown in Illustration 2. Be sure to make good, tight electrical connections for accuracy in voltage measurements.
Illustration 2. Connections for exciter reactor winding test.2. With the AC voltage source "ON", check and make a note of the voltages at X2, Y2, and Z2. Also, check the source voltage across H1 and H3.3. If the voltage of the AC source is not exactly 115 Volts, find the correction factor and multiply the voltages in the chart by this factor.Example: If the AC source voltage is 119 Volts, the correction factor will be 119 ÷ 115 = 1.038. Multiply the chart voltages by 1.038.
4. Check the X2,