SEAL-O-RING 1144427 - Caterpillar

Optional NEMA 3R Enclosure
Some transfer switches may utilize a NEMA Type 3 enclosure. This type of enclosure is dust-tight, rain-tight, and sleet or ice resistant. They are intended for use outdoors to protect the enclosed equipment against windblown dust and water.Remote Control Circuit
Remote Control Circuit DiagramAlso see Fast Test information in the "Operating Instructions" section of this manual. The optional Remote Control Circuit permits the operator to perform a normal test of the system from a selected, convenient, remote site.When the remote control switch is activated, the transfer switch then sends the signal to start. When the standby power source is available, the transfer switch will operate to that source, and continue to operate from that source until the remote control switch is returned to normal.The double pole, single throw (DPST) switch is customer supplied. Use stranded copper wire to connect the Remote Switch to the transfer switch. Recommended wire gauge size (AWG) depends on the length of the wire and is shown below.Return To NORMAL Bypass (For Use With Microprocessor Based Controls)
During automatic operation and following a normal power source failure, the generator will start and transfer to the standby source will occur. Under normal automatic operating conditions, restoration of normal source voltage and re-transfer back to that power source can occur at any time.Under certain conditions, it may be undesirable for re-transfer back to normal to occur such as in a manufacturing plant. The optional Return To Normal Bypass overrides automatic re-transfer back to the normal source on restoration of that power source.When normal source has been restored, the operator must initiate a return to normal transfer and generator shutdown by actuating the RETURN TO NORMAL pushbutton switch (mounted on the door). Return To NORMAL Bypass Operation Description:1. NORMAL Power Available, Generator Stopped: Transformer reduced STANDBY source power is not available to transfer mechanism terminals B1 and B2. Relay K2 is de-energized and its normally-closed contacts K2 are closed. Relay K1 is de-energized, its normally-closed contacts are closed, and its normally-open contacts are open. The Wire #199/199A circuit (between the Utility Voltage Sensor and the Microprocessor Based board) is closed and a "NORMAL Voltage Available" signal is available to the latter.2. NORMAL Power Lost, Generator Running: Transformer reduced STANDBY voltage is available to transfer mechanism terminals B1 and B2. Relay K2 energizes and its normally-closed contacts open. The Wires #199/199A circuit is held open by Relay K2 action.3. NORMAL Power Restored, Generator Running: With the engine-generator running, Relay K2 remains energized and its normally-closed contact remains open. The "NORMAL" voltage Available" signal that would normally be delivered to the Microprocessor Based (or In-Phase Monitor or Programmable Logic) board is not available. That circuit board "thinks" NORMAL source voltage is not available and provides no action to re-transfer the LOAD or stop the engine-generator.4. Return to Normal Pushbutton Closed: When the operator closes the pushbutton switch, Relay K1 is energized by reduced STANDBY source voltage. The normally-closed K1 contacts open, to de-energize Relay K2. The normally-open K1