User manual

AlfaSpid Rotator www.alfaradio.ca Page 7

Bench Testing of Control Box

The control box is normally expected to be operated from a 13.8 Volt DC

supply, however it may be operated from other unregulated DC or AC

sources as well. The output of supply source must be from 13.8 to 24 V,

6 Amps minimum.

The polarity of the power to the control box input leads is not critical, as

a full wave bridge rectifier on the input will provide the proper polarity to

the electronics.

TIP: Because of several steering diodes in the motor path, the voltage

delivered to the motor (neglecting wire loss) will be about 1.4 volts less

than the power supply voltage. For longer runs and/or thin wiring a

higher voltage (up to approx 24V) to the control unit is beneficial. A

simple way to estimate if the voltage to the motor is adequate is by

timing the rotation. Under no or a very small load, the 360 degree

rotation time with 12V DC at the motor is about 120 seconds (2 minutes).

With 24 V DC is about 60 seconds (1 minute). A DC Ammeter in the

motor lead is also useful. It should indicate between 2 and 3 amps with

a small load. On windy days or heavy load, the current may fluctuate up

to 3 to 5 amps per motor.

Notes – testing and troubleshooting

Azimuth:

Pressing

should make the rotator move clockwise.

Pressing

should make the rotator move counter-clockwise.

If rotation is reversed, switch lines 1 and 2 on the back of the controller.

Impulse sense lines (3 & 4) have no polarity concerns.

Elevation:

Pressing

should make the rotator move up.

Pressing

should make the rotator move down.

If rotation is reversed, switch lines 5 and 6 on the back of the controller.

Impulse sense lines (7 & 8) have no polarity concerns.

Part of the overload protection circuitry involves removing motor power if

the controller receives no sense indication. If the motor turns for a few

seconds and then you hear the relay in the control box drop out, the

motor has either stalled or there is a problem in the impulse sense

wiring. The controller has not detected motor movement.

It is highly recommended to ground the Control Box.