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Author Topic: Motor drive for small radar  (Read 3244 times)

AlanT

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Motor drive for small radar
« on: March 02, 2015, 12:20:31 pm »

Can anyone help?....


I'm looking for a cheap small motor with gearbox to drive a small radar on the Graupner Sydney Star.
The one recommended by Graupner is very expensive and hopefully there is a cheaper option available.


Many Thanks


Alan

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Stavros

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Re: Motor drive for small radar
« Reply #1 on: March 02, 2015, 01:19:29 pm »

Have a look at component shops web site in the motors section


Dave
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Calimero

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Re: Motor drive for small radar
« Reply #2 on: March 02, 2015, 01:43:38 pm »

I ordered a bunch of these: http://www.ebay.co.uk/itm/111397413754


Haven't gotten them yet but dang at that price it's worth a shot. Maybe a little too fast for radars.
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rsm

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Roger

chas

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Re: Motor drive for small radar
« Reply #4 on: March 02, 2015, 11:26:06 pm »

I bought an old cine camera from a car boot for a couple of pounds. Half  an hour to dismantle then I had a beautiful miniature motor and gearbox, plus lots of other useful bits.
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AlanT

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Re: Motor drive for small radar
« Reply #5 on: March 03, 2015, 01:43:30 am »

Thank you all very much for taking the time to reply.
Lots of great options to look at. I'm sure I will find a suitable unit.


Regards


Alan
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roycv

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Re: Motor drive for small radar
« Reply #6 on: March 03, 2015, 08:39:03 am »

Hi have you thought of using an old servo?  The electronics can be cut away, maybe also some plastic limiting the amount the arm can turn.  The motor connected direct to a power supply so that it can turn continously.  The servo box can be cut down as well.

If you use a fine spring steel wire loosely connected from servo to radar the servo can be hidden below and out of sight.  I would think the wire drive would go unnoticed in the s/structure.

I bought some very small servos at 4 for £10 on the Internet which would also be easy to convert.
regards Roy
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Mark T

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Re: Motor drive for small radar
« Reply #7 on: March 03, 2015, 06:04:05 pm »

These are good and very small:


http://www.ebay.co.uk/itm/261661531669?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT


What a cracking little motor - Here's a question though, if my circuits are 12v how would I reduce this down to 3v??

Time Bandit

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Re: Motor drive for small radar
« Reply #8 on: March 03, 2015, 06:34:43 pm »

How about one of these adjustable step-down regulator you can buy at ebay for like 2$.
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regards

Tobias

flashtwo

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Re: Motor drive for small radar
« Reply #9 on: March 03, 2015, 07:45:36 pm »

Hi, here is one from a reliable British source:

http://www.technobotsonline.com/solarbotics-gm6-offset.html

Notice it can run as slow as 7RPM.

You could run it from a dedicated battery cell of perhaps 1.2v (or multiples of), which would save dropping the volts through a resistor.

You can drop the volts by putting the resistor in series with the motor. I would get a selection of resistors of the 2watt range 47R, 100R and 220R and combine them in series to get the desired speed.

See http://www.maplin.co.uk/search?text=metal+film+2W&x=0&y=0 for 2watt resistors.

Make sure your power supply won't be overloaded and run down by the additional 50 to 150mA these motors take.

Ian
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