Toroidal power supply and Gecko stepper questions

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18 May 2021 17:04 #209366 by txtrone
If I want to upgrade my power supply and stepper drives first, and maybe (or maybe not) the motors at a later date, could I go with a 70V toroidal power supply that has more wattage than I need? The drivers and motors will only use the wattage/power which they are set for and that they draw, correct?

This is the power supply I am thinking of getting. www.antekinc.com/ps-8n70-800w-70v-power-supply/    ( I am open to suggestions though) 

As for drivers, I am thinking about upgrading to the Gecko GR214V... once again, I am open to suggestions.

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18 May 2021 18:24 #209374 by aleksamc
no, they will overheat

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18 May 2021 18:41 #209379 by txtrone

no, they will overheat


Even if the drivers are set to the correct amperage?

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18 May 2021 19:37 #209385 by aleksamc
Motors has nominal voltage, you can't overacceed it.
But if you don't believe me, you can try.

You always can decrese voltage on toroidal transformer.

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18 May 2021 19:51 #209387 by txtrone

Motors has nominal voltage, you can't overacceed it.
But if you don't believe me, you can try.

You always can decrese voltage on toroidal transformer.


I wasn't asking about the voltage, but rather the wattage. Could I have extra wattage that I do not need now, but I might need later if I were to get higher amperage motors.

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18 May 2021 20:11 #209391 by tommylight
Wattage = does not matter as long as it is not under the requirements
Voltage = for a toroid at 70 DC ( check this, 70V AC is not the same as 70V DC, website does not say but assuming DC ) and 80V geckos (again assuming they are 80V) is not the best idea, i would not go anything over 50V for any Gecko with 80V rating. Gecko used IRF740 MOSFET's on the outputs with VCE of 100V so any spike like pressing the e-stop while the machine is moving would blow them up with anything more than 60V supply.
But, there was a schematic on their website for a braking resistor and relay to prevent that, and that worked perfectly.
I liked them a lot and used a lot of them till a friend of mine brought 7 or 8 of them blown up as he did not bother to add the braking ( and Geckos website does not mention that much). The good thing is i was able to fix all but one of them (could not find the mosfet driver IC here) and Marius ( i think that was the name of the owner ) was very helpful on cnczone.

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18 May 2021 20:17 #209392 by rodw
I'm running motors at 90 volts and they have not overheated (well they have but we only make them work when they need to so they cool down in time)

I am not a fan of Gecko because I don't live in the US so don't need to wave the red, white and blue. Personally, I think they are a bit dated now.

Typically, your total motor amperage can be about 40% higher than the rated power supply amperage.

Maybe go with 20 amps for future proofing

I would eliminate the DC rectifier in the power supply quoted and just use a bare toroid with an AC compatible driver The LAM Technologies DS1076A (6 amp - NEMA 34) and DS1073A (3 amp NEMA 23/24) with a 55 to 60 Volt Toroid is a perfect combination. The DC voltage to the motors will be 40% higher (77v to 84V) You will need to wire in 4 inputs to joint fault signals and also 4 outputs and another of Rod's custom components to enable the Lam Boost feature. This lets the motors idle at lower current when at constant velocity.

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18 May 2021 20:23 #209396 by txtrone

You will need to wire in 4 inputs to joint fault signals and also 4 outputs and another of Rod's custom components to enable the Lam Boost feature. This lets the motors idle at lower current when at constant velocity.


What do you mean by Rod's custom components?

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18 May 2021 20:24 #209397 by txtrone

Wattage = does not matter as long as it is not under the requirements
Voltage = for a toroid at 70 DC ( check this, 70V AC is not the same as 70V DC, website does not say but assuming DC ) and 80V geckos (again assuming they are 80V) is not the best idea, i would not go anything over 50V for any Gecko with 80V rating. Gecko used IRF740 MOSFET's on the outputs with VCE of 100V so any spike like pressing the e-stop while the machine is moving would blow them up with anything more than 60V supply.
But, there was a schematic on their website for a braking resistor and relay to prevent that, and that worked perfectly.
I liked them a lot and used a lot of them till a friend of mine brought 7 or 8 of them blown up as he did not bother to add the braking ( and Geckos website does not mention that much). The good thing is i was able to fix all but one of them (could not find the mosfet driver IC here) and Marius ( i think that was the name of the owner ) was very helpful on cnczone.


What drivers would you go with?

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18 May 2021 20:44 #209400 by rodw

You will need to wire in 4 inputs to joint fault signals and also 4 outputs and another of Rod's custom components to enable the Lam Boost feature. This lets the motors idle at lower current when at constant velocity.


What do you mean by Rod's custom components?


To get the most out of these drives, you need to enable the boost feature. This requires a non standard component like you are using for your down draft.

Tommy uses Lam drivers and he was the one htat put me on to them

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