linear actuator

Long time since I've posted but I need some help. I have a HTS (Houston Tracking System) linear actuator off of a C-ban
satallite dish. It has 6 wires coming out of it; 2 large (~16 ga.) [red and white] and 4 smaller wires [od green, green, yellow and bare] I'm pretty sure that the red and white are the power leads and the others are sensor wires. I also think that it is 24 volts dc, here is where I have been having problems; I can get the actuator to move in only one direction no matter which wires I use for positive and negitive. Is there a couple of the other wires that need to be dealt with in order to make this motor turn in the oppsite direction? Any help would be appreciated.
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so if you make the red plus and the white minus, it moves? and if you make the red minus and the white plus it still moves in the same direction?
tell us exactly what you did, maybe we can help - your guess that the two larger wires are power is good - sometimes the ground is part of the circuit (e.g. red to ground or white to ground)

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You must measure the inductance . I do it with a cheap
HPS-10 O'scope and a low power
DIY pulse generator .
you can figure anything in a few minutes .
In an emergency , you could spark a battery
across the unknown wires . If the battery is
big , limit with a resistor , this will trigger
the scope , do it 10 times .
Throw out all the readings that are not similar .
You have characterized those wires , it only takes
me seconds to figure a 60hz or a D.C. motor/circuit .
Of course you must have experience .
I look at the size of a motor , try to guess , is it Series- universal
or a stepper , or a treadmill motor ( 100 VDC , slow , multiple
poles on each field magnet ) .
You must have these characteristics as images , in your head ,
or you'll just waste time .
When you use a battery and R , only , you cant see the differences
in inductance aka Inductive reactance aka resistance at fast rise
times .
So , dont guess at wiring til you have a low cost
pocket O'Scope hooked up .
The old HPS-5 , uses a simple 64 by 128 , NO backlite
But B.G. Micro sold me 50 LCD's ,
when i get time , i'll hook 10 LCD's to HPS-5
, with a DE-MUX , so the scope thinks its got
one LCD , but signal is sent to 10 LCD's in sequence
every microsecond , the "next" sequencial
LCD gets the data . This is one really long time base !
HPS-10 uses a diff type , i cant find it .
When i get time ill DIY power supply to push up
ground on HPS-10 , cause to read D.C. voltages
is a pain . Good scopes can turn a knob ( D.C. offset aka vertical
position ) ..
It has an mcu , so why cant it compare the 2 peaks and
read out the frequency ! Lame programmers at
Velleman ..
BTW dont buy model 518 from ..
Mine broke MOSFETs quick .
Fooled ya , 518 is no longer sold , it has a design defect .
They wont return my money , they offer to change MOSFETs
til its just outside of warranty , then ....
ALSO looking for tapered rollers . Google charges to list
sellors ... NO , they dont have one sellor . I wasted
hours ...
Need a high angle ( 5,6,7 ) tappered roller , I.D. = 2.75 or
3.0 for aircraft propellor hub* .
DIY airplane did a redesign , it now folds to 8 foot , for
loading into 65 foot motor-sailer .
For years , i pained over dinghies ,
but a pontoon plane ( 2 pushers ) is more convenient .
Pontoons are wide spaced , and wings fold forward .
Propellors must be light wieght . DOM tube is light , and
unlike aluminum , has no lower limit , in fatigue .
Steel has a limit , below 44,000 psi , steel makes a good
spring , it will NOT fatigue crack . Aluminum WILL fail ,
it has NO lower limit . Think about that , next time you fly .
Maybe thats why they dont make planes ,
w/ "structural" skin . Its under your feet , huge I-beams and rings
and formers ..
Anyone have numbers for the carrier tapered rollers from
10 ton trucks ? They make good lathe head bearings .
Another silly arguement from a racer , he said a motorcycle
engine cant make 10 HP and win a economy race .
The waste in a car engine is reciprocating losses , the oil
heat indicates ...
But Yamaha / Honda 60 cubic inchers , have such light
wt pistons , pins , rod ( upper 50% )
they can run at 8-9 thou and win econo races , at 10 HP .
Simply retard intake cam 51 degrees ( Honda car i-VTEC has
51 Degree retard ) . It nixs pumping losses .
The scream from R1 yamaha is mostly the strate cut primary
gear , teeth cut into one of the crank wheels . Old bikes ran clutch
at 33% , pocket rockets cant , need about 60-70%
They must speed up the clutch or burn the C' in minutes .
They are slowly moving toward friction plus dog , as soon as
the RPM is matched close , dogs engage , take load off
friction plates , stop slipping .
My XR650R will get 2 air cylinders on rear . spring has NO progression ,
its only one "rate' .....
A common car shock is rervalved to pump oil one way , is located inside air cylinders .
This transfers to air pump. no matter how little you bounce ,
every bounce , you pump 200psi air into tank
Reverse the coolant flow , it MUST enter head , near exh valve .
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I would measure the resistance between all the leads. The big leads are most likely the power leads, but the smaller wires might go to relays that control the speed and direction.
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I've had a few of the C-band dish actuators apart, and the leads going into the gearbox were for DC motor power, and a feedback device which may be either a potentiometer or a reed switch assembly that's aactivated/switched by a rotating magnet disc.
If you remove the gearbox cover, the wiring should be fairly obvious.
The older actutors that I'm familiar with (1980s models) had an indoor power supply (separate from the tuner) that was the power source for the motor, and also had the reversing relays in it. The feedback leads went to the tuner IIRC.
It's not entirely clear, what you described as the actutor only moves in one direction regardless of the DC polarity change. I think you are seeing that with one polarity, the actuator moves, and with the other polarity, it doesn't move (not that it moves in the same direction as the first polarity).
Inside the actuator tube there is a ballscrew, and since ballscrews are easily moved by external forces, there needs to be a braking system to insure that the actuator holds it's position.
The actuator tube probably isn't designed for disassembly, but there are likely to be a pair of spring coil mechanical brakes wound to fit snuggly onto hubs. The ones I saw (when I used an angle grinder to disassemble the actuator), were the type of brakes that hold a hub in the way that turning a rod inserted into a spring will turn freely in one direction, but be gripped by the spring in the other direction.
If water has gotten into the actuator and caused the spring coils to rust, they aren't likely to be operating as intended.
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mike wrote:

Its probably a series wound motor. It only turns in one direction regardless of the supply polarity.
Check continuity between the smaller wires. One pair probably drives a solenoid which engages a forward/reverse gear shift. That wire pair will show from 50 to several hundred ohms (the coil resistance).
The other wires might be for limit/position/sensing switch(es). They'll appear to be either open circuit or less than a few ohms. Once you get this thing rotating, you can check their function.
The bare wire is probably a ground. Verify this by checking continuity to the case. Some of the small wire functions might use this as a common.
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