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Author Topic: Can the motors pictured below be used with the AstroEQ?  (Read 2026 times)

Peter802

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Can the motors pictured below be used with the AstroEQ?
« on: April 16, 2017, 16:43:19 »

Hi I purchase an AstroEQ and need advice about the connections fro the EQ to the motors. The motors have RJ45 connectors which have 6 pins and the EQ has 4 pins.

The motors are on a Bresser EQ5 goto mount.

Many thanks

« Last Edit: April 16, 2017, 16:45:35 by Peter802 »
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Peter

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TCWORLD

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Re: Can the motors pictured below be used with the AstroEQ?
« Reply #1 on: April 16, 2017, 18:17:21 »

You'll need to first work out what the pin connections for the motors are, and make sure they are stepper motors.

If they are bipolar motors you should find either two or four pairs of pins which have a low-ish resistance (<100Ohm). If they are unipolar you will find four pairs with a low-ish resistance, of which each pair of pairs will have a wire in common. For reference, see the picture half way down this AstroEQ tutorial page.

Once you have identified the pin-out, you will need to map those on to the AstroEQ pins. The AstroEQ RJ11 connectors have the following pinout:

Code: [Select]
1   2   3   4   5   6
N/C  A   B   B   A  N/C

In the above "A" are one coil, and "B" are the second coil. For bipolar if you have two pairs then you can connect one pair to A and the other to B, if there are four pairs you will need to work out which to pairs to connect together which is not straight forward. If you have unipolar then you will need to leave the centre pin of each coil unconnected.

It doesn't matter which end of the A coil goes to which wire (2 or 5), and which end of the B coil goes to which wire (3 or 4), just be consistent between motors. Flipping a coil around will simply change the direction the motor spins, which can be corrected for in the config utility.
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Tom Carpenter (AstroEQ)

Peter802

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Re: Can the motors pictured below be used with the AstroEQ?
« Reply #2 on: April 18, 2017, 10:36:53 »

Hi Tom.

Thanks for the information, not that it means to much to this old git at present!!

I have attached some more photos.

Questions.

Where do I stick the probes to measure for resistance?

Is the meter set on the correct range to achieve said readings?

Will I have to solder new sockets to achieve the connection, if so what sockets will I require?

I am back in the UK now so can purchase the items that I require.

As you can see from the photographs there are only 2 wires connected to the motors.

Do you have any idea what type of motors these are. They are numbered with. CP7AD.

Sorry to be a pain but am desperate to get this working whilst I am in the Uk.

Many thanks

Peter

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TCWORLD

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Re: Can the motors pictured below be used with the AstroEQ?
« Reply #3 on: April 18, 2017, 11:55:04 »

Hi Peter,

Those aren't stepper motors. They look to be DC motors with an encoder, so probably some form of Servo drive.
 
You'll need to buy some stepper motors for the mount as you won't be able to use the motors you have with the AstroEQ.

Kind Regards,
Tom.
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Tom Carpenter (AstroEQ)

Peter802

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Re: Can the motors pictured below be used with the AstroEQ?
« Reply #4 on: April 18, 2017, 13:33:24 »

Tom. I thought that this would be the case.

Do you have any recommendations as to what I need to enable me to pull this all together?

Would it be best to switch to belt drive?

I.e. The best motors and fittings required.

Thanks Peter
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Peter802

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Re: Can the motors pictured below be used with the AstroEQ?
« Reply #5 on: April 19, 2017, 08:40:38 »


Tom.

Would these motors be suitable for my needs?


0.9deg Nema 17 Stepper Motor Bipolar 0.9A 36Ncm/50oz.in 42x42x39mm 4-wires DIY

Many thanks.

Peter
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