[ullbergm]

I found this ebay item and i was curious what you guys thought about the specs.

It looks nice and its only $50..
http://www.tracopower.com/products/tsl.htm

Traco Power TSL480-155PX Industrial Power Supply
Input: 93-264VAC Auto-ranging, 50/60Hz
Output: 48-55VDC Adjustable, 480 Watts, 10A

Screw-Terminal Input and Output
Universal Input Voltage
Output Voltage Adjustable
Short-to-Ground for Negative Voltage!
Metal Case (Aluminum), 9x5x5in
Easy Snap-On Mounting on DIN-Rails

-155 Model Is Custom -148 Model with Wider Operating Temperature Range
Low Harmonic Emissions on Input ('P' in the model#)
Extremely Low Output Ripple and Noise ('X' in the model#)
High Efficiency
Overload Protection
Parallel Operation Possible
CE Compliance to European EMC and Low Voltage Directive
Compliance to EN 61000-3-2 (PFC)
Conducted Emissions to EN 55011, Class B, and FCC Part 15 Level B
Noise Immunity to EN 50082-2
Safety Approvals to IEC 60950, EN 60950 (SELV) UL/cUL 1950, and UL 508

These power supplies are brand new, still in box. They were used both as bench power supplies on our manufacturing/test line, and as in-unit 48v power for a product that we manufactured for the telecom industry. Unfortunately, we are closing the business and are forced to sell our entire inventory of these $300+ units for pennies on the dollar.

edit: Added url to manufacturers spec

[balsaman]

what will you use this supply with? It's too high a voltage for most drivers. It would be a good match with some gecko's. What steppermotors/servos?

Eric

[ullbergm]

Originally posted by balsaman
what will you use this supply with? It's too high a voltage for most drivers. It would be a good match with some gecko's. What steppermotors/servos?

Eric

i've got a stepperworld controller and the mosfets are rated at 15 amps. It can handle 50v.

[balsaman]

You will need some serious current limiting resistors. Which motors?

Eric

[ullbergm]

The motors are nema 23 180oz-in, 4 volt, 2 amps.

If my calculations are correct im going to need some 22 ohm resistors, 2 per motor. They should be atleast 100W.

The resistors come up to something like $137 on mouser.com and the powersupply $50.

One bonus with those powersupplies is that you can hook them together in parallel. and at $50 they are not very expensive.

Do you have any suggestions where to get heatsinks? mouser doesnt have anything like what i'd want (one big heatsink for all the resistors to attach to)

[balsaman]

Your calcs are correct for resistors needed. Your powersupply will need to be 12 amps min. for 3 motors. You may be better off to forget the resistors and get a xylotex board which won't need any. You won't be able to run 48 volts on the xylotex tho.

Also price the 11 ohm, 50 watt resistors, two in series will make 22 ohms, 100 watts. I am not sure which way is cheaper.

If you can find an old stereo amp sometimes you can find heatsink material in them...

Eric

[umrk]

Dale resistors? This HS might work.

If thats too small, one big HS is usually hard to find and expensive when you do. All Electronics has some individual HS's you could use, CAT# HS-78, for $2.50 ea.

Are you going to fan force cool the HS? Thats a lot of watts to burn up.

mike

[ullbergm]

Originally posted by balsaman
Your calcs are correct for resistors needed. Your powersupply will need to be 12 amps min. for 3 motors. You may be better off to forget the resistors and get a xylotex board which won't need any. You won't be able to run 48 volts on the xylotex tho.

Actually i have a xylotex board but i was thinking that running at 48v would be better than running at 28v. Would you agree with that?

Also price the 11 ohm, 50 watt resistors, two in series will make 22 ohms, 100 watts. I am not sure which way is cheaper.

looking at mouser i found 100, 200 & 300 watt, but no 50..

I believe the resistors need to be 88 watt, would you think 100w is enough with some good cooling? or do i need to go with 2 11 ohm 100w resistors to increase the rating?

[balsaman]

100 watt 22 ohms will be fine. Put a fan on there. They will be HOT. This is normal.

I agree that 48 volts will give you better top end speed. Speed always costs money...

Eric

[ullbergm]

Originally posted by umrk
Dale resistors?

I'm looking at the Xicon low inductance (either alum housing or the thick film ones)
http://www.mouser.com/catalog/616/394.pdf

This HS might work.

If thats too small, one big HS is usually hard to find and expensive when you do. All Electronics has some individual HS's you could use, CAT# HS-78, for $2.50 ea.

Thanks, i may go with one per resistor and mount them next to eachother so that the fans can cool all of them.

Are you going to fan force cool the HS? Thats a lot of watts to burn up.

Yes, i figured it'd have one fan pushing air in over the heatsink and one pulling it out on the other side.

[ullbergm]

Originally posted by balsaman
100 watt 22 ohms will be fine. Put a fan on there. They will be HOT. This is normal.

I agree that 48 volts will give you better top end speed. Speed always costs money...

Eric

hehe,
yep, looking at a 48V 12A PS on mouser will run you over $500.. i had pretty much given up on that until i found the ebay one for $50.

Would you suggest mounting 2 of them in parallel so that it'd be 20A? you said it would need 12, will 10 be ok?

i guess for $50 it'd be safer to just put in 2..

[balsaman]

One would be pushing things.....

If you do go with 2, put one on the z axis and the other on the x and y.

You could also go 24 volts on z and 48 volts on x and y....assuming you already have a 24 volt supply kicking around.

Eric

[ullbergm]

Originally posted by balsaman
One would be pushing things.....

If you do go with 2, put one on the z axis and the other on the x and y.

You could also go 24 volts on z and 48 volts on x and y....assuming you already have a 24 volt supply kicking around.

Eric

What i was thinking was to put two of them together in parallel (they support that, up to 5 powersupplies can be hooked together) and get 48V 20A plus the redundancy. Do you think there would be a problem with that?

edit: The controller does not support 2 power supply inputs. there is only one input.

[ullbergm]

one more question about steppers and amps..

When the motor is sitting still, but powered up, how much power does it use?

For example, my motors are 2A, how much will they pull when they are not moving?

Thanks,
Magnus

[balsaman]

2 amps per phase. That's 4 amps total per motor. It doesn't matter if it's moving or not, same power.

If it's the FET 3, it does support two powersupplies, one for Z and another for x and y....no? I had one of those boards. I had to put jumpers in mine to make it run on one supply I think.

If the powersupplies support being in parallel, then go for it.

Eric

[ullbergm]

Originally posted by balsaman
2 amps per phase. That's 4 amps total per motor. It doesn't matter if it's moving or not, same power.

If it's the FET 3, it does support two powersupplies, one for Z and another for x and y....no? I had one of those boards. I had to put jumpers in mine to make it run on one supply I think.

If the powersupplies support being in parallel, then go for it.

Eric

Hehe, it took me this long to figure out that it is 2 amps/phase, i had been thinking that people were doubling the power to be on the safe side. thanks for clarifying that for me.

Actually i take that back, i think it does support 2 power sources. I've got a FET-4 and it has a separate powersupply for the 4th axis if i remember correctly.

The powersupply definately supports a parallel configuration. And then i can say that i have redundant power supplies for my motors ;-)

[umrk]

Hmmm, Your going to spend, abt $325 for a controller, resistors, heatsinks, and additional new (second) PS... putting most of that power up in heat and taking up more room. (abt $425 cost with 2 PSs)

For $75 more you could have 3 Gecko G210, 7A max, w/microstepping for much smoother moves (even in full step mode they output 10 microsteps), and more torque at speed with PWM over the resistor current limiting. At 2A you could just heatsink them to a aluminum enclosure. And of course one new 48V 10A ps. (Abt $500 cost with 1 PS)

You would no longer need the second fan, plus your only paying s/h from 2 sources, instead of 4 knocking it down closer to a $40 difference. Heck, you probably wouldn't even need the one fan.

Are you sure thats what you want to do?

mike

[ullbergm]

Originally posted by umrk
Hmmm, Your going to spend, abt $325 for a controller, resistors, heatsinks, and additional new (second) PS... putting most of that power up in heat and taking up more room. (abt $425 cost with 2 PSs)

For $75 more you could have 3 Gecko G210, 7A max, w/microstepping for much smoother moves (even in full step mode they output 10 microsteps), and more torque at speed with PWM over the resistor current limiting. At 2A you could just heatsink them to a aluminum enclosure. And of course one new 48V 10A ps. (Abt $500 cost with 1 PS)

You would no longer need the second fan, plus your only paying s/h from 2 sources, instead of 4 knocking it down closer to a $40 difference. Heck, you probably wouldn't even need the one fan.

Are you sure thats what you want to do?

mike

Actually i already have the controller and 3 uni-polar motors.. if i was starting from scratch i would probably go different. But now you have me thinking...

[umrk]

Geckos will drive unipolar steppers too.

mike

[ullbergm]

Originally posted by umrk
Geckos will drive unipolar steppers too.

mike

So how big of a power supply would i need?

The motors are 2 amps / phase.

Edit: Does a chopper use that much less? With the stepperworld controller we figured we'd need 12 amps..

I had read that a chopper uses 20% of the rated power, doesnt that mean that it loses motor torque?