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Antenna Mast Group

We will now trace the electrical circuits of the antenna mast mast group.

Be fore we get started you will need to print four copies of the next slide, and have your colored markers.

The schematic is broken down into five sections.

Mast control box

Distribution box

Hydraulic component assembly (HCA)

Pneumatic component assembly (PCA)

Limit switches

When troubleshooting the manual will tell you to replace one of the major components, but you must be able to inform the instructor which component inside the major component is defective.

GO ORDNANCE !!!GO ORDNANCE !!!

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AC Compressor Components

a. CB2, CB6; CB for protectionb. T1; Step down transformerc. CR1; Full wave bridge rectifierd. C1; Capacitore. S4; Compressor pressure disconnect switch at 95psi opens and shuts down the compressor.f. A5; AC Compressorg. S4; (Control box) Mode switch set to AC auto.h. K1; Relay (Control box)

AC Compressor

At 95 PSI the S4 opens and shuts down the compressor.

Place the S4 in the AC auto position.

The AC power comes into the mast from the J1 pin C, 115 VAC plug.

The transformer now has 115VAC on the primary side. The transformer will supply power to the CR1 diode, which will apply DC volts to the AC compressor. Pick up the circuit on the secondary side of the transformer.

The AC compressor is now running.

We will now turn on the light on the control box. Pick up the circuit at the C1, capacitor.Now the K1, relay in the control box will energize to keep the DC

compressor from turning on while the Switch is in the AC auto. Pick up the circuit from the K1.

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DC Compressor Components

a. CB1; CB for protectionb. K1; Relay PCAc. S1; Compressor pressure disconnect

switch at 85psi opens and shuts down the compressor.

d. A1; DC Compressore. S1; (Control box) Mode switchf. S5; DC Mode switchg. S2, Tank pressure switch at 85psi turns

the tank pressure indicator light on.

DC Compressor

At 85 PSI the S4 will open and shut down the compressor by de-energizing the K1 relay.

Tank air pressure Ind.

At 85 PSI the S2 switch will reverse and turn on the pressure indicator light on the control box. Pick up the circuit just below the indicator light on the control box.

Place the S4 switch in the DC position, and close the S5 DC mode switch.

The DC comes from the truck batteries into the J4 plug pin C. This is negative potential.

First we must energize the K1, relay.

K1 is now energized, it’s contacts close and turns on the DC compressor. Pick up the circuit at the connection just before the DC compressor.

The DC compressor in now running. We will now turn on the light on the control box. Pick up the circuit at the connection below pin C on the J4 and go into pin M on the J5.

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Raise the Mast in AC Mode

Raise mast Components are:

a. K1; AC relay

b. A1; AC hydraulic pump

c. S1; Mast Erection switch

d. S6; Mode switch

e. CR1; 90 VDC

f. S3; Anti-jog switch

g. Lower valve

Before the mast can be raise in the AC mode

K1 relay must be energized it is energizes with DC.

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Extend the Mast in AC Mode

Extend the mast components are:

a. A2, Extend valve

b. A4, Safety valve

c. 100 degree limit switch

d. S3, Extend switch

Mast Out

Mast Raise AC

Energize K1 The pump in now running with 90 VDC from the CR1, but the mast will not raise until we get power to the raise valve.

When the mast reaches 90 degrees the interlock strut switches close.

When 10 PSI is in the mast the S3 will reverse and cut power from the raise and lower switch.

Safety Valve

Place the S1 in the raise position.Start at J4 pin C, 24 VDC. To energize the K1.

K1 is now energized, it’s contacts close and provides a path for the AC hydraulic pump to operate.

Start at the J1 pin C, 115VAC. To energize the AC hydraulic pump.

We will now apply power to the raise valve. Pick up the circuit at the connection above the CB6.

When the mast reaches 100 degrees the switch will open and stop the mast from raising, by disconnecting power from the raise valve and the raise switch.

When the mast raises past zero degrees the switch will close and apply power to the A4, Safety valve.

We will now energize the A4. Pick up the circuit at the connection below J4 pin C.

A4 closes so air can go into the mast.

Place the S3 in the out position, and pick up the circuit just before J8 pin C.

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Retract Mast in DC Mode

Retract the mast components are:

a. A3, Retract valve

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Lower the Mast in DC Mode

Lower mast Components are:a. K2; DC relayb. A2; DC hydraulic pumpc. S1; Mast Erection switchd. S6; Mode switche. S3; Anti-jog switchf. Lower valveg. 10 Degree Limit Switchh. S2, Limit override switch

Before the mast can be lowered in the DC mode K2 relay must be energized.

Retract Mast DC

Energize K2

Lower Mast

Place the S3 in the in position.

Start at the J4 pin C.

The A3, retract valve is now energized, and air is being bleed out of the mast.

When air in the mast drops below 10 psi the anti-jog switch will reverse back to the normal position and allow power to the mast lower switch.Place the S1 in the lower position,

and place the S5 in the DC position.

Pick up the circuit at the connection below the J4 pin C to energize the K2 relay.

K2 is now energized it’s contacts close and apply power to the DC hydraulic pump.

We will now energize the DC hydraulic pump. Pick up the circuit at the connection just above the CB6. The pump is now running, but the

mast is not lowering.We will now energize the lower valve. Pick up the circuit at the connection just below the DC hydraulic pump.

Remember the 10 degree limit switch will open and stop the mast from lowering so the operator can store the antenna.

After the antenna is stored the operator must press the limit-override button and the lower switch at the same time to continue lowering the mast.

Pick up the circuit at the connection just above J2 pin G.