Stock Taig Stepper Specs?

[benedict]

I've got an older 4-axis Taig CNC mill I bought back in late 2000. It's got 200 oz-in steppers on it, the same ones the mill shipped with. I'm in the process of converting to a Keling KL-G540-48 controller, but I'd like to keep the original motors. I'm having rotten luck finding the specs on the motors the mill shipped with. Does anyone have any pointers, or better yet a spec sheet for those motors? I'm trying to get everything in order before the new controller shows up so I can get rolling with it.

Thanks!

Tom

[Jeff-Birt]

They are made by Linn Engineering part# 5718L-10D-01 they are marked as 1.00A. They are good quality motors but looking at the product page for this series: http://www.linengineering.com/LinE/c...tors/5718.aspx, it looks like they are likely custom made for Taig. Given that they are 200 oz-in 1A motors that indicates the inductance is really high. Check out the 5718L-01S for a similar motor which is rated at 15 mH per phase. In that configuration they are NOT well suited for a G540.

If you can rewire the motors in parallel it would be better but you will still have a pretty high inductance motor for the G540. I use/recommend some 2.8A 166 oz-in motors for Taigs, they work great with a G540.

Just curious what type of power supply came with your controller. I've seen quite a few folks hawking 12A power supplies for a G540. Given that the G540 has a fast blow 7A internal fuse a power supply that could really put out 12A seems like a waste.

[Crevice Reamer]

Hi Jeff.

Originally Posted by Jeff-Birt They are made by Linn Engineering part# 5718L-10D-01 they are marked as 1.00A. They are good quality motors but looking at the product page for this series: http://www.linengineering.com/LinE/c...tors/5718.aspx, it looks like they are likely custom made for Taig. Given that they are 200 oz-in 1A motors that indicates the inductance is really high. Check out the 5718L-01S for a similar motor which is rated at 15 mH per phase. In that configuration they are NOT well suited for a G540. If you can rewire the motors in parallel it would be better but you will still have a pretty high inductance motor for the G540.

If the above specs are correct, rewiring the motors to Bipolar Parallel would make a 1 A 127 Volt motor into a 2A 61V motor. This is well within the specs of the G540 and it should run fairly well with 48-50V.

Originally Posted by Jeff-Birt I've seen quite a few folks hawking 12A power supplies for a G540. Given that the G540 has a fast blow 7A internal fuse a power supply that could really put out 12A seems like a waste.

You are comparing apples to oranges. The G540 cannot draw more than 3.5A per motor. The POWER SUPPLY however must supply enough amps for total motor consumption.

A single 3.5A motor connected to a 12A PSU will only draw 3.5A of the PSU capacity. FOUR 3.5A motors connected to the same PSU will need to draw a minimum of 8.4A. At no time will the above G540 be asked to draw more than 3.5A per motor. This is far below the 7A rating of the internal fuse, so that does not apply to the PSU size calculation.

I feel that a ten Amp PSU is more than adequate for any G540 use, but even if the PSU was rated for 20 Amps, the extra capacity would not cause any problem.

CR.

[Kelinginc]

Originally Posted by Jeff-Birt They are made by Linn Engineering part# 5718L-10D-01 they are marked as 1.00A. They are good quality motors but looking at the product page for this series: http://www.linengineering.com/LinE/c...tors/5718.aspx, it looks like they are likely custom made for Taig. Given that they are 200 oz-in 1A motors that indicates the inductance is really high. Check out the 5718L-01S for a similar motor which is rated at 15 mH per phase. In that configuration they are NOT well suited for a G540. If you can rewire the motors in parallel it would be better but you will still have a pretty high inductance motor for the G540. I use/recommend some 2.8A 166 oz-in motors for Taigs, they work great with a G540. Just curious what type of power supply came with your controller. I've seen quite a few folks hawking 12A power supplies for a G540. Given that the G540 has a fast blow 7A internal fuse a power supply that could really put out 12A seems like a waste.

it is a 48V, 12.5A power supply. it will work with this motor
http://www.kelinginc.net/ControlSystem.html

[benedict]

I have an unfortunate habit of asking questions like this when I'm not at home and can't lay eyes on the actual parts. Here's what's installed on my mill:

All four axes have Shinano Kenshi SST57D5101 motors on them. I'm pretty sure this was typical of the Y2K era Taig CNC mills. Shinano Kenshi apparently no longer makes this motor, but as things turn out they have pretty good documentation on it. (Which was amazingly easy to find once I had the part number... Sorry, still slapping my forehead for getting jazzed about my new controller while I was away from the shop and couldn't answer my own questions.)

Here are the specs on the motor:

Shinano Kenshi SST57D5101
1.8 deg/step
9.2-12.9 V/Phase
0.7-1.0 A/Phase
9.2 Ohms/Phase
20 mH/Phase
14.3 kg/cm Holding Torque
430 g/cm Rotor Inertia
NEMA 23 Frame

Just to double check my math, here's what I get for my calculated values:

Wired as half-winding:

Max running voltage:
32 * sqrt(20mH) = 143.1V (The 48V supply in the Keling unit is well under this)

Current set resistor (using 1.0A and selecting next lowest resistor):
47 * 1.0 / (7 - 1.0) = 7.83 kOhm
I've got a drawer of 7.5kOhm resistors.

Wired as full-winding:

Max running voltage:
32 * sqrt(40mH) = 202.4V (Still safe)

Current set resistor (getting fuzzy here... 0.5A?):
47 * 0.5 / (7 - 0.5) = 3.61 kOhm
I've got a drawer of 3.32kOhm resistors.

As far as I can tell I should be well within spec for the G540 and the 48V supply that comes in the Keling controller. But by all means let me know if any of my assumptions or calculations are wrong.

Thanks again for all the feedback, and my apologies for asking questions before laying eyes on my mill and reading off part numbers. Feeling kinda foolish, but I'm glad for the help.

Tom

[Crevice Reamer]

Hi Tom.

I think you have somehow got the wrong idea about the supply voltage. It's not about having the supply voltage to be UNDER the max motor voltage to be safe. What you want ideally, is for the motor best voltage to match the 50V max of the G540 (Or maybe just a LITTLE above) and use a 48-50V power supply. If you are correct on those inductance figures, then you cannot use these motors with the G540--they will perform miserably.

CR.

[Jeff-Birt]

If the above specs are correct, rewiring the motors to Bipolar Parallel would make a 1 A 127 Volt motor into a 2A 61V motor. This is well within the specs of the G540 and it should run fairly well with 48-50V.

Well, that is kind of what I said. In series configuration that are definitely not a good match. IF they can be rewired in parallel configuration they would perhaps be OK. Judging by the new information the OP provided his motors wired in parallel would still have a per phase inductance of 10mH. While they will work OK they are above Geckos suggestion of about 3mH for max power output from the drivers. If I had these motors on hand I would use them though.

You are comparing apples to oranges. The G540 cannot draw more than 3.5A per motor. The POWER SUPPLY however must supply enough amps for total motor consumption. A single 3.5A motor connected to a 12A PSU will only draw 3.5A of the PSU capacity. FOUR 3.5A motors connected to the same PSU will need to draw a minimum of 8.4A. At no time will the above G540 be asked to draw more than 3.5A per motor. This is far below the 7A rating of the internal fuse, so that does not apply to the PSU size calculation.

No, actually I am quite correct. Saying that a G540 can draw 8.4A through a 7A fuse is nonsense. The G540 has a 7A fast blow fuse, it will never, ever, ever draw more than 7A, the 7A internal fuse prevents that from happening. The problem with using rule-of-thumb formulas is that you have to understand the assumptions they make and what the numbers they give you actually mean.

The formulas that Gecko puts out (the ones everyone are so fond of using) give a good estimate of the voltage to use to drive a given motor and get the most power with least heating. It in now way implies that it is the max voltage that can be used. As long as you do not exceed the current or temp specs of the motor or driver then your OK, the extra voltage will produce more heat than power form the motor though.

In a similar manner the formlas that are floating around to size a power supplies current capaicty assume you are sizing a linear unregulated supply. When sizing an unregulated supply you have to oversize the current capacity to keep the supply voltage in the proper range (the more current you draw from an unregulated supply the more the voltage drops.)

If your using a good quality switch type power supply then there is absolutly no reason to use a 10A or 12A supply. It won't hurt anything but you spending more money for capacity that the G540 will never use.