FLOOR-STANDING SWITCHGEAR Caterpillar


Operation

Usage:

Introduction

The floor-standing switchgear is used to either connect or disconnect a generator set from an electric system. Gauges on the switchgear operate when the generator set is in operation. The indications on the gauges are the amount of electric power produced by the generator set.

The floor-standing switchgear is a cabinet with both an upper and a lower panel (door) with hinges. Because of the hinges on each panel, either the upper panel or the lower panel can be opened either separately or both panels together.

The floor-standing switchgear is designed for voltage phase rotation 1, 2 and 3 or A, B and C. Some gauges and switches will not correctly operate if connected in voltage phase rotation 1, 3 and 2 or A, C and B. When the switchgear is viewed from the front (toward the gauges and switch controls) the voltage phase rotation of the cables, from the generator to the circuit breaker and the bus risers from the circuit breaker to the bus bars is from left to right 1, 2 and 3 or A, B and C. Always remember when the switchgear is viewed at the back the voltage phase rotation is from right to left 1, 2 and 3 or A, B and C. The voltage phase rotation of the bus bars is from the front (toward the gauges and switch controls), 1, 2 and 3 or A, B and C. If the switchgear has a neutral bus, the neutral bus is after phase 3 and the voltage phase rotation from front to the rear is 1, 2, 3 and N or A, B, C and N (Neutral).


BACK COVER REMOVED FROM SWITCHGEAR
A. Bus riser for phase 1. B. Bus riser for phase 2. C. Bus riser for phase 3. N. Neutral bus.

Basic Switchgear

The gauges on the upper panel (door) are: A.C. voltmeter (1), A.C. ammeter (3) and frequency meter (2). Voltage adjust rheostat (4) and ammeter-voltmeter switch (5), for the generator set phases, are also on the upper panel. A circuit breaker switch (6) is through an opening in the lower panel. Inside of the cabinet, behind the circuit breaker, are the three current transformers (8), two potential transformers (7), fuses (9) and a terminal strip.


SWITCHGEAR UPPER PANEL (DOOR)
1. A.C. Voltmeter. 2. Frequency meter. 3. A.C. Ammeter. 4. Voltage adjust rheostat (control). 5. Ammeter-voltmeter switch (position for each generator base).


UPPER PANEL (BACK SIDE)
1. Voltmeter. 2. Frequency meter. 3. Ammeter. 4. Voltage level rheostat. 5. Ammeter and voltmeter switch.

The voltmeter (1) is the visual indication of the voltage in one phase of the electrical system from the generator set when it is in operation. The ammeter (3) is a visual indication of the current (load) in one phase of the electric system from the generator when the generator set is in operation and the circuit breaker, on the switchgear, is closed.

The positions OFF, 1, 2, and 3 of ammeter-voltmeter switch (5) are to connect the voltmeter and ammeter to the phase, of the electric system, in a relation to the number position of the switch.

Voltage adjust rheostat (4) is a control that is used to make changes in the amount of voltage (voltmeter shows changes) from the generator set when it is in operation.

Frequency meter (2) shows the cycles per second of the electricity (speed of the generator set) when the generator set is in operation.


LOWER PANEL OPEN
6. Circuit breaker. 7. Potential transformers. 8. Current transformers (three). 9. Fuses (F1, F2 and F3).

Circuit breaker (6) is a switch that can be closed or opened to connect or disconnect the generator from the electric system. The switch can be closed or opened when the generator set is either in operation or when it is stopped.

Wires from current transformers (8), around the cable or bus risers of each phase from the generator set, connect to selector switch (5) and ammeter (3). These transformers make a reduction in the current from the generator to the ammeter. The indication on the ammeter is the amount of current in either the cable or bus risers from the generator.

Wires from the secondary windings of potential transformers (7) connect to frequency meter (2), switch (5) and voltmeter (1). The voltage from these transformers is at the correct level of voltage needed to operate the frequency meter and the voltmeter. The level of the voltage from the potential transformers is in a direct relation with the level of voltage in a phase from the generator set and the indication on the voltmeter is the same as the voltage in the phase.


UPPER PANEL OPEN
5. Ammeter and voltmeter switch (on upper panel). 10. Fuses (F4, F5).

The identification on a wire in a circuit, in the switchgear, is either a number and a letter or a letter and a number that is followed by number 1, number 2, number 3, etc. For example 3T1 on the wire (see the wiring diagram) is between the fuse (F3) and the potential transformer (PT2). The wire from (PT2) to Fuse (F5) is 3T2. The wire from (F5), in the same circuit, is 3T3. The identification of the circuit is on the wire, near the wire terminal, anyplace in the switchgear.


BASIC SWITCHGEAR WIRING DIAGRAM

Switchgear With Optional Parts

There are floor-standing switchgears that have many optional parts. The upper panel (door) can have many more gauges and controls added to the standard three gauges and switch.

The A.C. voltmeter (1), frequency meter (2), A.C. ammeter (3), voltage adjust rheostat control (14) and the ammeter-voltmeter switch (13) are always parts in the upper panel.

The watt-hour meter (4) makes a record of the electric energy that was used. When the generator set is in operation, the record of the electric energy used constantly increases.

When the generator set is in operation, the indication on power factor meter (5) is a ratio. The ratio is the difference between the kilowatts from the electric set and the product of 1000 X (times) the indication on the ammeter X (times) the indication on the voltmeter.

When the generator set is in operation, the indication on wattmeter (6) is the amount of electric energy from the generator set. When the electric energy from the generator set increases, because of an increase in the electric load, the indication on the wattmeter increases.

Synchronizing switch (9) is used to either connect synchroscope (7) and synchronizing lights (8) to the line leads (cables) from the generator set and to the bus bar in the switchgear or to disconnect the circuits for the synchroscope and synchronizing lights.

Synchroscope (7) is used when it is necessary to close the circuit breaker, on the switchgear, to add the electric energy from the generator set to the electric load in the bus bars of the switchgear (from another generator set). When synchronizing switch (9) is ON and the rotation of the point in synchroscope (7) is slow and is in a clockwise direction, the electric speed of the generator set is just a little faster than the electric speed of the generator set connected to the bus bars. When the point in the synchroscope is vertical with the point at the top, close the circuit breaker to put both generator sets in a parallel operation.

Synchronizing lights (8) have the same use as the synchroscope. When synchronizing switch (9) is ON and the electric speed of the generator set is near the electric speed of the generator set connected to the bus bars the synchronizing lights go ON and OFF again and again and etc.

When the synchronizing lights get dark (OFF) no more than four to six times in one minute the electric speed of the generator set is approximately the same as the generator set connected to the bus bars. When the synchronizing lights are dark close the circuit breaker to put both generator sets in a parallel operation.


UPPER PANEL WITH OPTIONAL GAUGES AND SWITCHES
1. A.C. Voltmeter. 2. Frequency meter. 3. A.C. Ammeter. 4. Watt hour meter. 5. Power factor meter. 6. Watt meter (kilowatts). 7. Synchroscope. 8. Synchronizing lights. 9. Synchronizing switch (for synchronizing lights and synchroscope). 10. Lights for circuit breaker condition. 11. Switch to operate the circuit breaker. 12. Governor control (engine rpm). 13. Ammeter and voltmeter switch (for each phase). 14. Voltage adjust rheostat (control). 15. Reverse power indication light. 16. Alarm OFF-ON switch. 17. Elapsed time meter. 18. Engine alarm lights (not normal conditions). 19. Automatic start-stop control panel.

Lights (10) do not operate at the same time. The lights are for the condition of the circuit breaker. One light (red) shows when the circuit breaker is closed. The other light (green) shows when the circuit breaker is open.

Switch (11) is a remote control to either close or open the circuit breaker.

Governor control (12) is turned in a clockwise rotation to increase the rpm of the engine for the generator set. Turn the control counterclockwise to decrease the rpm of the engine.

If for some reason a component in the electric system makes more electric energy (reverse power) than the generator set, a reverse power relay (safety device) opens the circuit breaker on the switchgear. Reverse power indicator light (15) shows that the reverse power relay opened the circuit breaker. A reset switch, when pushed, makes the reverse power indicator light go OFF.

Alarm disconnect switch (16) can either stop the sound from the alarm or connect the alarm into the pre-alarm circuit for any failures in the engine lubricating and cooling systems.


UPPER COMPARTMENT PANEL OPEN
1. A.C. Voltmeter. 2. Frequency meter. 3. A.C. Ammeter. 4. Watt-hour meter. 5. Power factor meter. 6. Watt meter. 7. Synchroscope. 9. Synchronizing switch. 10. Lights for circuit breaker condition. 11. Switch to operate the circuit breaker. 12. Governor control (engine rpm). 13. Ammeter and voltmeter switch. 14. Voltage adjust rheostat (control). 16. Alarm OFF-ON switch. 17. Elapsed time meter. 18. Engine alarm lights (not normal conditions).

The numbers in elapsed time meter (17) are the indication of the amount of hours (and parts of an hour) that the generator has operated.


AUTOMATIC START-STOP CONTROL PANEL
20. Overcrank light (OCL). 21. Low lubricating oil pressure light (OPL). 22. Overspeed light (OSL). 23. Automatic control switch (ACS). 24. High water temperature light (WTL).

The engine control on the automatic start-stop control panel (19) is an automatic control switch (ACS) with four positions. The positions of switch (23) are: OFF/RESET, AUTO, MAN and STOP. Each light (20), (21), (22) and (24) goes ON only when a not normal condition in the engine stops the engine. The light for the condition in the engine that stopped the engine is ON even after the engine has stopped. Switch (23) must be moved to the OFF/RESET position for the light to go OFF. Each light will go ON, for a light test, when the light is pushed in and held in.


PART OF SWITCHGEAR LOWER PANEL (DOOR)
25. Control lever (on the circuit breaker). 26. Battery charger switch. 27. D.C. Ammeter (for the battery charger).

The operation for each position of the automatic control switch (ACS) and for some of the not normal conditions in the engine that stop the engine are in the section AUTOMATIC START-STOP.

Control lever (25), through the lower panel, is on the circuit breaker in the lower compartment. The control lever is used to either close the circuit breaker and connect the generator set to the electric load or to open the circuit breaker to disconnect the generator set from the electric load. The control lever (on the circuit breaker) shown is on a switch gear that has a remote switch to operate an electric motor on the circuit breaker. The operation of an electric motor closes or opens the circuit breaker when the remote switch is moved to the CLOSE or OPEN position.

Battery charger switch (26) has an OFF and an ON position. The switch is used when it is necessary to charge the batteries (engines without alternators).

D.C. ammeter (27) shows the amount of amperes from the battery charger to the batteries.


SWITCHGEAR LOWER COMPARTMENT (PANEL OPEN)
25. Control lever (circuit breaker). 26. Battery charger switch. 27. D.C. Ammeter (back). 28. Risers (to busbars). 29. Bars (from generator load leads). 30. Potential transformers. 31. Battery charger. 32. Breaker control transformer.


SWITCHGEAR WIRING DIAGRAM (NOT COMPLETE)

The identification on a wire in a circuit, in the switchgear, is either a number and a letter or a letter and a number that is followed by number 1, number 2, number 3, etc. When a component is added to a circuit in the switchgear, the number that follows the second number or letter identification on the wire increases by one number. For an example: 1C1 on the wire (see the wiring diagram) is between the current transformer (CT1) and the watt hour meter (WHM). The wire from (WHM) to reverse power relay (RPR) is 1C2. The wire from (RPR), in the same circuit, is 1C3. The identification of the circuit is on the wire, near the wire terminal, anyplace in the switchgear.

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