Antenna Rotor wont turn

[letterman]

I have a fairly new antenna rotor (about 2 years old). The box is turning the dial, but the antenna is not rotating. The wire connections are ok on the control box, so I assume a wire broke at the motor from wind. However, before I go on the roof, I want to test the voltage output at the control terminals. What should I expect for voltage, and is it AC or DC?

I should also mention that it's about zero deg. outdoors, and was wondering if all or most rotors simply will not turn when it's this cold. Anyone know?

And, lets say that I am seeing power at the control box. Can a meter on the resistance range show whether I have a connection both inside and outside the rotor motor. (in other words, show the motor windings). Being this frikkin cold outdoors, I want to do as much testing from indoors first......

BTW It's a THREE wire type (I know some have four) I cant tell you the brans, because it's not on the control box (duh....)

Thanks

LM

[Mikepier]

Not much you can do at this point since you can't go on the roof. That is where you should test if you have voltage. The motor might have a "dead" spot in it, or it might be frozen or have a loose connection. Wait until you can go on the roof but in the meantime do not attempt to turn the rotor from the box otherwise you might burn out the motor.

[dicko]

Bah! I hate 3 wire rotors....

On mine, any time the temperature dropped below 32 degrees, it stopped turning. I could predict to the instant when it would stop by looking at a thermometer. I only assume water gets into it and freezes the shaft. I never could see any when I replaced and inspected it. Oh yeah, it would never turn the full 360 degrees either. There's no position sensor so it doesnt know if its in sync with the control box. This was my second unit. The first unit died with some other problem that I forget.

Its just a dc motor. one wire is ground and then the other two have

24v applied to either wire depending on direction of turn. If possible, just wait untill warmer weather and see if it starts. working. Wait, the only fix I knew was to replace the unit. So replace it now, wait and replace it later, the end result is the same.

-dickm

[TimR]

Most antenna rotors are mounted very badly. They are designed so the antenna sits on top of the bearing with nothing to take the side load.

As wind moves the antenna back and forth, the bearing (which is designed ONLY to resist a downward force) has to restrain the large antenna from moving back and forth. The bearing fails and burns out the motor.

If you mounted the rotor on the mast, went up a couple feet and ran the shaft of the antenna through an additional bearing, your rotor would last forever. Some ham antennas are done this way.