I recommend Rutex drivers.

[ynneb]

I have the Rutex drivers complete with the mother board and relay board setup.

While I havnt yet installed the servos on the machine, I have tested the servos on the table.

I am very impressed at how strongly these drivers control a servo.
by this I mean the speed that they will change the direction of the servo, with no overrun whatsoever.

To look at the board you would never believe they are rated at 100v 20a for each servo.

I am still learning about these drivers and will post information as I go.

[ynneb]

Another picture of the heat sink and fan I attached to my Rutex drivers. It probably doesnt need a fan but I had one lying about so I put it on anyway.

[Konstantin]

Hi benny.
Looking great, are those the cheapOclifton servos?

So how much did you spendo on your setup and what have you bought exactly drivers, cables, encoders?

[ynneb]

Well they maybe the cheapo servos, I just dont know, I paid $450 US for them. They are Amatec brand. I have since found out that they were excess stock for reel to reel computer tape drive machines.

Someone said to me that they may have cost the seller $10 bucks a piece originally. I could feel ripped off, but the seller has been very supportive to me in advice. No need for me to get caught up in regret, they will do what I want, and I will have to learn to shop a bit harder in the future. I shouldnt complain about entreprenurialship. I was happy with the purchase before I knew the facts.

The encoders are Renco encoders. They are open ended encoders. I didnt realize that open ended encoders wont allow long runs of cable. I am told about 2 M run maximum. Rutex has a conversion card that can make the encoders run on longer cables. The convertion cards cost $19 each.

The encoders came already fitted on the servos. The encoders are 2000 pulse per revolution. I put a mark on the shaft of the servo, and on the servo itself. I ran the servos for 9 million pulses and when they stopped, both the marks lined up perfectly. Seeing this is probably normal to most CNCers but for me it was amazing that it could do this. Just seeing this has made me feel very excited about my project.

The other amazing thing about the setup is that the servos can run at full speed and then come to an immediate stop with no overrun. This can be achievd by tuning the driver board with the servos. The overrun results are then displayed on the computer.

You asked about cables. I am running sheilded power cable to the encoder, and a seperate shielded counter cable to the same encoder. I am told this is a good method of practice, to avoid signal interferance. The servo supply cable are plain old extension cable cut to suit. I guess they should be shielded too to stop leaking interfereance.

[kdoney]

Do you have a close up of the cabling done on the db9? I'd like to see an example of the pullup resistor connections

[Konstantin]

Thanks for filling in the details benny.
If you happen to have more things to say of pics to post they re very welcome.
Keep it up
So the whole deal was about 450 bucs?

Konstantin

[ynneb]

Kdoney, when you say db9, I presume you mean the J2 connection for the encoders that connect to the driver.

I insereted the two 470R resistors in the cable itself and heat shrinked them in. It was a messy process.

I used the directions from the rutex pdf file downloaded from the rutex site. I must admit its drawn in a confusing way, however I must have got it right first go.

When in testing mode you are meant to put 2 x 100R resistors across pins 1 and 2 and across 3 and 4. of J7
At first I just pushed the resistors in the connector itself, but it was very fragile and the conections were tempramaental, so I just made up a connector with the resistors soldered in.

Does this help, or do you need me to list the actual connections and the pins that they all went to?

EDIT: Oh the driver setup cost $638. so the whole deal was more than a $1000. I could have bought a great TV surround sound system for that

[trubleshtr]

Ynneb, Don't feel bad, I too, bought the same motors, but have not received mine yet. I was unaware of the open end encoder............Looks like I might be buying those cards you mentioned for $19.
I was planning on running them with 320 Gekco drives. glad to hear they keep their accuracy.

[ynneb]

Trubleshtr, If you havnt yet recieved the servos, then email him and ask for the other encoders to be put on them. He has said on this forum that he would do it for free. I didnt take up the offer because I am in Australia and didnt want to wait, nor did I want to have to fit the new encoders. If yoiu read his second post in this thread you will see his offer Stepper or servo moters (Lots of ?'s)

I think the geckos dont handle enough amperage for these servos, and from what I have read the Rutex are more fogiving of errors.

EDIT: I forgot to mention the prower supply. The servos are rated at 40volts constant, and 60 volts peak. Speaking with someone else who used Amatec servos, his advice was to run the voltage a bit higher to get them to perform. I had a transformer wound for 36 amps constant and 36 volts AC. After the rectifier it comes out at 50 volts DC. My servos dont even feel warm running off this setup.

Oh yes the power supply cost me $350 AU (80% less in US dollars) I was advised that you need 2000uf capacititance per amp to stabalize the ripple. I have about 14 capacitors in paralell.

[trubleshtr]

thanks for the info ynneb. I'm gonna email him now and ask for the 5v. encoders so I dont have to power them seperately. 14 capaciters, thats a little more that I was anticipating, is that also to control the regenerative power??

[vacpress]

He dosent really need "14" he jsut needs a certain voltage and capacitance.. for a big power supply, the capacitors can be massive, the size of a small can of coffee. he just used smaller ones in parallel. this makes them act as 1 capacitance.

[vacpress]

Oh!

Tell me, is there a surplus source for these motors? 10$ ? is that in some quantity?

details please?

thanks