Rotator brake delay for Ham Antenna Rotors

BRAKE PROTECTION FOR YOUR HAM II, III, IV, AND TAILTWISTER ROTATORS.



I'm not going to take credit for this. It has been around for years. You can buy one over the net. I looked for some kind of directions or plans for this mod for a long time. I think it was in a magazine in 1980. Anyway I wanted to build my own. It cost me about 7 or 8 bucks. To top it off it is really easy to build.



The Rotor manufacturer's instructions caution users to always let the motor coast to a stop before permitting the brake to engage



A rotor brake delay can save your rotor from being destroyed. The weight of your antenna can continue to turn your rotor slightly. If your brake engages during this coasting period. Or if your finger slips off the brake button it could be costly.





HERE we go.







You will be adding the part circled in BLUE



THE PARTS LIST

K1 is a relay, 24v dc,600ohm coil. I used part # R40-11D2-24 by NTE



C1 is a electrolytic capacitor, 1000uF,35v. I used part # NEV1000M35FF by NTE



R1 is a resistor, 150 ohm, 1/2 watt. I used HW115 by NTE



D1 and D2 are Diodes, 750mA, 600v, 1a, I used part # 1N4005 by you got it.



HOW IT WORKS



Pressing the brake release and then CCW or CW. D1 or D2 will charge C1 through R1 and hold K1 on which holds the brake off. When CCW or CW is released the power will stop and K1 will continue to hold the brake off until C1 discharges.



First press the break release then either CCW or CW. At this point your brake is released and the rotor is turning. Now you can release the break button and continue holding the CCW or CW button. Your antenna is turning and will continue to hold the brake off. Turn the antenna to the desired direction and release the CCW/CW button.

You can also hold both like your most likely use to.

On my Brake delay the break will automatically engage in about 8 seconds. after installing the delay it would be a good idea if you time the break delay to make sure it's delay is at least 3 seconds. You can change the value of C1 to extend the delay time. If you have a tailtwister control box then you will notice the green brake light will stay on when the break is off and turn off when the brake is on.

 

Dennis N6KI made a good point in the schematic.
The schematic shows the relay contacts N.C. ( Normally Closed ) But the description seems to indicate that the relay contacts are N.O.( Normally Open ) then CLOSE when brake lever is initially depressed.


Thanks Dennis, good point.
It should show (normally open). Then when CCW or CW are pressed in conjunction with the brake release it adds power and becomes (closed) thus allowing power through to release the brake.

I can't edit the original post so here is the best I could do in paint shop



.

 

Also, can you tell us what the relay contact Voltage and Current ratings are ?
No problem Dennis.


Contact rating : 2 Amp @ 120 VAC, 28 VDC

Find it here its a NTE R40-11D2-24
http://www.nteinc.com/relay_web/pdf/R40.pdf







.

 

I installed a green pilot lamp on the controller front panel to show when the brake is "off" (in mechanical release) because I can't hear the relay drop.
Once rotation has started, you don't need to hold the brake key operated.
The brake release will stay operated as long as the left or right rotation key is held on, once rotation has started.
Timing is about 10 seconds +/- to brake 'ON', in my circuit.
I control 2 rotors thru a remote switch powered by 12v from a seperate supply built into the controller. 12V off is #1, 12v on is #2.
Remote switch is 2 4 pole double throw relays in a weather proof box out at the closer tower base for the Mosely Tri band and a control cable to the far tower, for 6 and 2m beams.
You can see the direction meter change-over direction in response to the switch-over.

 

Yep sounds about right. I'm glad it worked out for you. 73

Ron / N6DCN

 

Very good post! You should have made this an "article," and maybe it's not too late to do that.

I might point out that "NTE" is not a manufacturer of anything; so although they list and brand lots of stuff, they don't make any of it.

There are zillions of relays that will do this job and can be found in the DigiKey and Mouser catalogs, and many other places. It's not a very critical application.

 

Yah I just put the specs and a part # just in case someone didn't know what to get. The NTE # was on everything I got at my local Metro Electronics. It seems to be easy to cross referance the NTE #s.
How are things going with you Steve

 

Good, Ron, how are you?

I know I'm good when I wake up in the morning and read the Obituaries and see my name isn't there.

 

Thanks for reminding people of that.

I have HDR 300's which have a manual brake switch that locks in place. It is not a spring back button.

I dispensed with the need to push the brake button at all in my HDR 300 rotors. When you mash the direction, it unlocks the brake and then applies voltage to the motor.

After about 10 seconds after stopping the turning the brake comes back on by itself.

I did this because of guest operators who would mess things up. They would use the rotor, NEVER relock the brake, and the wind would eventually spin the rotor past the stops.