AR22-R rotator

[Malcolm G6ANZ]

In between rebuilding my R1155 I am refurbising my old AR22R rotator. So far all is well, Ive cleaned off all the old solid grease and the mechanism now runs smoothly. In the control box there is a capacitor that looks as though its seen better days. I assume this is the motor run or start capacitor. From the diagram it is C1. Would a 150uF motor cap work here? eg https://www.amazon.co.uk/Capacitor-1.../dp/B07PXJPG87

I'm also considering replacing the micro switch, (S3) a standard V3 roller type and the capacitor across it. As these parts will be high in the sky it makes sense to replace them now while access is easy.

Malcolm

[Radio Wrangler]

It's a low voltage single-phase AC motor, so the capacitor is somewhat larger in C and lower in V than most easily found start/run capacitors. It might be a bit of fun finding a replacement. C value is important as it's a phase shifter, suiting the start winding inductance.

David

[its ur aerial]

I concur with Davids comments above, its quite a large capacitance value for a start/run cap and it is important to match both the 120uf and 140uf values.
Fitting the wrong value will make the motor will run rough and get very hot, very quickly.
I assume there's not enough room to fit more than one start/run cap and make the C value up ?
My only suggestion as a supply source, is look on the RS Components siteIf not, I don't know.

Ken G6HZG.

[Malcolm G6ANZ]

Ken, its only a single capacitor, the value printed is its range 120-140uF. The one I linked to is a 250v 150uF although higher voltage the capacitance is OK.

[David G4EBT]

You might find this video of use Malcolm.

It covers the restoration of an AR22, and starts off by explaining the replacement of the motor start capacitor, which is described as the ‘Achilles heel’:

https://m.youtube.com/watch?v=4W0A9nRIi2M

(CDR were later taken over by Hy-Gain, and at least some spares are still available).

I used one back in the 1980s. It was bought from a bring and buy rally stall as ‘spares or repair’. I had to replace the mains transformer in it, due in part I think for it having been 220V. I’d have thought that wouldn’t have mattered, given that each time the rotator was used it was only drawing power for a couple of minutes or so. The head unit needed stripping cleaning and re-greasing.

It worked a treat and never skipped a beat for some years till I moved house and sold it.

Good luck with it.

[its ur aerial]

I thought I saw three wires from it, so assumed given the markings it was two caps, give it a try, according to the person on the video, he claims its not critical ?

Ken G6HZG.

[Radio Wrangler]

You could try Mouser or Digi-key, being US-based as suppliers of lower voltage higher capacitance motor capacitors.

They ship to UK and handle taxes etc from their end.

David

[dodgy-dxer]

Hygain in turn are now owned by MFJ

Fred

Originally Posted by David G4EBT

(CDR were later taken over by Hy-Gain, and at least some spares are still available).

[dodgy-dxer]

I fixed the bigger Ham 3 with pretty much that same capacitor and it ran for ages longer until I need something "bigger"

50 years ago before we had the benefit of internet experts and Amazon the "dodge" was to use a twin capacitor can of the same value and 2 diodes to stop the caps being reverse charged

2 AR22s in my home village were fixed like that and lasted years more

Probably came for the late lamented "Technical Topics " in the 70s

Fred
G4BWP

Originally Posted by Malcolm G6ANZ

In between rebuilding my R1155 I am refurbising my old AR22R rotator. So far all is well, Ive cleaned off all the old solid grease and the mechanism now runs smoothly. In the control box there is a capacitor that looks as though its seen better days. I assume this is the motor run or start capacitor. From the diagram it is C1. Would a 150uF motor cap work here? eg https://www.amazon.co.uk/Capacitor-1.../dp/B07PXJPG87

I'm also considering replacing the micro switch, (S3) a standard V3 roller type and the capacitor across it. As these parts will be high in the sky it makes sense to replace them now while access is easy.

Malcolm

[ex 2 Base]

I had a large preowned rotator and a 3 element beam can't remember the make but made in USA. The fault on the motor was the 150 mF capacitor which I replaced with a motor start type, it never let me down. Motor start capacitors are high value special electrolytic type with short time rating, but the motor is only used for a minute or two, so I didn't have any problems. Motor rewinder will supply you or so will RS, Farnell or maybe Rapid. Ted

[Jon_G4MDC]

Fred (dodgy-dxer)'s post intrigued me so I decided to have a go at simulating it.

The first attempt was a fail. I just managed to fully charge 2 capacitors with DC.
Silly really but if you want a capacitor re-former.

2nd attempt with a dual capacitor worked but I realised it was assuming a common +ve terminal. There are not many of these around.

3rd attempt used can common negative. You can probably find these.

Of course today this might be done with capacitors scavenged from Monitors or PC PSUs. They have quite high capacitance values and they are very small for the working Voltage. I doubt that a common can matters at all when taking this route.

[dodgy-dxer]

Nice one Jon!

[Jon_G4MDC]

I should add the parts Voltages etc were just chosen at random. I wanted to see how it might work. There is a very old AR40 in the shed somewhere that might need it.

[Malcolm G6ANZ]

Using the second circuit from G4MDC and 1N4007 diodes I have rebuilt the capacitor. It works as it should. Not before time, I was playing with the rotator proving I could set up the 'north' point and the motor stopped working. The original cap had failed.
PS Jon, your callsign is my initials. (MDC)
Malcolm

[Jon_G4MDC]

haha nice one Malcolm. I'm very glad it worked and thanks to Fred for kicking off the idea.