Mounting encoder

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Hi folks


This weekend I was trying to mount a USDigital optical encoder (E3 model) to
a S28 magmotor DC motor. As the motor axis sticks out on both sides, I was
trying to mount it to the top of the motor. As expected, there is no
mounting hole on the motor, so before I do something bad to the motor, what
do you think is a good way to mount it?

Should I drill the motor? I don't really know how thick is the metal on the
top of the motor. Or should I glue it? The encoder is made of plastic (black
policarbonate I believe) and the motor is metal (maybe aluminum?), so what
type of glue should I use? It would be nice if I could remove it later on if
I wanted.

Cheers

Padu



Re: Mounting encoder


I would use Epoxy Resin. You can get it from most hardware stores. It
bonds just about anything to anything.

Re: Mounting encoder

"Brendan Gillatt"

You mean the one that comes in two parts you have to mix? how easy is to
remove it later on if I need? I was going to ask you about thermal
properties, since I suspect the motor will get warm eventually, but now I
remenber that I've used JBWeld on my motorcycle's radiator, I think it's
kind of the same right?

Cheers

Padu



Re: Mounting encoder



Use a collar around the motor which can be taken off, moved, adjusted, is
cheap, is light, will do the job. Come on down to my shop and we'll make one
for you.

Wayne



Re: Mounting encoder



Yeah - one part's the glue, the other the fixer. This allows you to glue
things without any air present making even thick layers of glue very hard.


You'll probably never separate the two but as Wayne mentioned a
removable motor mount would probably be very handy.


Yeah - by the looks of it it's the same stuff.


Re: Mounting encoder


There is virtually no torque on the encoder, so a thin double-sided tape
works well. In fact, this is what US Digital sells for their smaller
encoder.

If you can find it locally other than in bulk, 3M VBH double-sided tape
is perhaps the best. After a day or so it cures and is generally as
strong as many epoxies.

-- Gordon

Re: Mounting encoder


     You can buy those motors with an encoder, you know.

     I'd suggest finding or making a thick washer that fits the encoder end
of the motor.  Drill and tap the washer with the desired mounting
holes.  Glue, solder, or spot-weld the washer to the end of the motor.
Then screw on the encoder.

                    John Nagle

Re: Mounting encoder


I did something similar to John's suggestion to mount E2 encoders on my drive
motors.  The motors had some threaded holes at the end, so I made some plates
that attached using them, and mounted the encoders as John describes above.

I actually made them out of the aluminum base plate from a 1/4" tape
cartridge.  I only needed a compass, hacksaw, file, drill, and tap.  I have
been very happy with the performance of US Digital products.

Jeff.
--
Jeff Shirley
spam-puppy@mindspring.com
"Bill Gates is filthy rich, but that doesn't mean I want to be married to him."

Re: Mounting encoder


Padu:

Double sided tape is actually good enough.  Just make sure that
you get the encoder properly centered.  USDigital typically
sells/provides a centering "tool" that slips over the shaft
and then you put the encoder over the tool.  Frankly, you should
have received the tools and double sided tape from your vendor.

My robot building partner and I recently purchased a couple of
US Digital encoders and they showed up without the centering
tool or the spacer (or the electrical cable).  A quick call
to the vendor resovled the issue.

By the way, we're using the LS7366 to keep track of each encoder.
The LS7366 may be a little hard to get, but it sure is easy to use.

My $.02,

-Wayne

Re: Mounting encoder

"Wayne C. Gramlich"

Wayne(s) and Gordon,

Thanks for the replies. It seems that double sided is the way to go then.
I called the motor manufacturer and they said if I wanted to drill the
aluminum plate I could do it safely up to 1/4", but I don't have the tools
to make a thread on the hole, and the adhesive tape wins in simplicity.

I got the centering tool, but they didn't provide the tape. It should be
easy to get from home depot or similar. I won't need an encoder chip for
now. I'm using the roboteq motor controller and they take care of the issue
(that's what I'm hoping for).




Re: Mounting encoder



Standard foam tape kinda sucks, but it will work in a pinch. It is not
dimensionally stable. However, it's usually not a big issue, unless you
notice the encoder rotating a smidge back and forth as the motor
reverses. Obviously that's not good.

I may start to sell VHB tape, cut to length, as I do Dual Lock. Most
places sell it by the roll, and at $100 a roll, it's expensive when all
you need is just a little bit of it.

US Digital usually sells the tool as a separate item, as it's cheaper if
you're buying in quantity. If all you get are two encoders, then it
makes sense to buy one tool, and two mounting adhesive discs. USD's
products are excellent, but their ordering options can be somewhat
bewildering. Especially for these new low-cost encoders.

I'm with Wayne on seeing the value in the LS7366. An encoder and counter
with a serial output. Finally! With your school connections you might be
able to get samples from the manufacturer, which is LSI
(http://www.lsicsi.com/encoders.htm ).

-- Gordon

Re: Mounting encoder

"Padu"

Thank you all for the suggestions.

I've ended up using a double sided tape that is good for metal too.
It seems pretty solid. I hope it stays like that with heat and time.

Cheers

Padu



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