0397532 JOHNSON LIFT AY,HYDRAULIC

Illustration 1 g00695380
When servicing or repairing electric power generation equipment:Make sure the unit is off-line (disconnected from utility and/or other generators power service), and either locked out or tagged DO NOT OPERATE. Remove all fuses.
Connect the light bulbs with rated voltage between the generator leads and the corresponding line phase. For example, connect terminal 1 to line 1 across the open circuit breaker.
Start the units that will be in operating in parallel. Bring the units up to speed. As the units approach the same speed, the lights will start to blink.
If the lights blink in sequence, one of the units is connected backward. To correct the problem, stop the units. Remove generator leads 1 and 3 at the circuit breaker. Exchange these generator leads. This reverses the direction of phase rotation. Terminal 2 should always be connected to line 2.
Both generators have the same phase rotation when the lights blink in unison. The first condition of "Initial Start-Up" has been met.
Adjust the frequency.The units that will be operating in parallel must operate at the same speed. Speed is proportional to the alternating current frequency.
Allow each electric set to run under load for about 30 minutes.
Adjust the governor control to give the rated frequency at full load.
Remove the load and check the high idle speed. The high idle speed should be approximately 2 to 5 percent above full load speed for governors that are equipped with droop. If these speeds cannot be obtained, contact your Caterpillar dealer.
For the most consistent results, repeat 2b and 2c until the second condition of "Initial Start-Up" has been met.
Adjust the voltage.The potentiometers should be at the initial settings. Refer to Operation and Maintenance Manual, "Voltage Regulators".Note: Make sure that the speed droop is identical for all the engines before adjustments are made to the generator.
Preset the unit for parallel operation by connecting the current transformer to S1 and S2 of the connector J2. Set potentiometer P1 for quadrature droop in the center position. Apply the rated load. The voltage should drop for 2% to 3%. Switch the positions of the two incoming secondary wires of the current transformer if the voltage increases.
The no-load voltages should be identical for all the generators that are operating in parallel. Connect the generators in parallel. Try to obtain a 0 kW power exchange by adjusting the speed of the generator. Try to minimize the circulating currents between generators by altering the voltage setting with potentiometer P2 or Rhe on one of the generators.Note: Do not change the voltage settings after this step.
Apply the available load. The setting is correct only if a reactive load is available. Equalize the Kilowatts or divide the rated power of the units proportionally by altering the speed. Alter the quadrature droop potentiometer (P1) to equalize the currents or divide the currents.Starting Multiple Units
Use the procedure for starting single units to start multiple units. Refer to Operation Section, "Single Unit Operation".Paralleling Multiple Units
Units may be paralleled at no load. Units may also be paralleled with units under load. After the initial conditions for start-up are satisfied, verify for the following requirements:
One of the governors can be an isochronous governor. Electronic load sharing governors are an exception.
Generators must have voltage droop compensation or cross current compensation.
Start the unit which will be paralleled.
Turn on the synchronizer lights.
After the engine has run a few minutes, bring the engine up to synchronous speed. This means that the frequency of the incoming unit will be the same frequency as the unit that is on-line. The synchronizing lights will begin to blink.Note: The frequency of the incoming unit should be slightly greater than the line frequency. This will allow the incoming unit to assume some of the load instead of adding to the system load.
By using the governor control, adjust the engine speed until the lights blink slowly.
The lights are off when the voltages of the two units are in-phase. At this point, quickly close the breaker while the lights are out.
Use governor controls to share kW load between engines.
Generator temperature will be stabilized in approximately 1 hour. After the generator temperature has been stabilized, adjust the voltage droop rheostat of each generator. This will share the reactive load and this will limit the circulating currents. Less droop increases the reactive current that is carried by the generator. Adjusting the voltage droop rheostat in a counterclockwise direction will decrease the droop. Adjusting the voltage droop rheostat in a clockwise direction will increase droop.