[skillalot]

Why in earth would you need 48V 20Amps to run a machine with 3 steppermotors???

[jips]

Why in earth would you need 48V 20Amps to run a machine with 3 steppermotors???

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[handlewanker]

Hi Jips......that 1 and 2 switch position is a puzzle......perhaps I should have had one too.

Unless you have the driver for the high speed spindle already installed in the electronics box there would be no reason to have a 2 position switch........it could be there in case you ever wanted to have the high speed spindle option........ the driver would then have to be an option and a DIY install along with the high speed spindle.......I opted for the high speed spindle but no driver was included in the package......it's still coming......the double way switch appears to be an afterthought.

This makes the set-up I have a bit tacky as now I'll have to install the driver in the box and a socket and a switch etc etc......I have 2 mains sockets on the back of the machine where the main power cable plugs in, but they don't have a switch.........one could be for the high speed spindle and the other for a 4th axis., but they still need to be switched.

Well they say when you get trouble it spreads out and is contagious.......now my electric power draw bar has stopped working.....totally dead.

So I stripped it off the top of the mill and shock horror.....what a schmozzle.........the motor on the PDB is 12 volts and the supply is 24 volts.........by upping the voltage the idea would be to give the motor more speed and power to push down on the draw bar.....for the short duration it works for.....only now it doesn't work........it failed when going up and left the tool locked in the spindle.

There is a capacitor on the input lines to the PDB to absorb some of the voltage surge, but as capacitors can instantly charge up it's not much use without a resistor in the line too.

If the motor has burned out, I wonder how/why..... it's only been used for a couple of cycles as I'm still not making chips, just doing a bit of practice G coding........it's only cycled on and off for approx 20-30 times in the last 3 months.

This will be a case for Skyfire and Co to handle as it's under warranty and I don't want to mess with the insides of the thruster mechanism to see what's gone wrong.

In the meantime I'll have to rig up a manual jury mechanism to get the tools in and out......and there's no way I'm going for an air solution......ever.
Ian.

[jips]

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[mactec54]

I made a diagram , sorry for the non standard drawing .



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Something not right with that wiring diagram, check for sure where that Ground wire is going to on the Transformer, and how many wires are on the input side of the Transformer

[jips]

Hi Jips......that 1 and 2 switch position is a puzzle......perhaps I should have had one too.

Unless you have the driver for the high speed spindle already installed in the electronics box there would be no reason to have a 2 position switch........it could be there in case you ever wanted to have the high speed spindle option........ the driver would then have to be an option and a DIY install along with the high speed spindle.......I opted for the high speed spindle but no driver was included in the package......it's still coming......the double way switch appears to be an afterthought.

This makes the set-up I have a bit tacky as now I'll have to install the driver in the box and a socket and a switch etc etc......I have 2 mains sockets on the back of the machine where the main power cable plugs in, but they don't have a switch.........one could be for the high speed spindle and the other for a 4th axis., but they still need to be switched.

Well they say when you get trouble it spreads out and is contagious.......now my electric power draw bar has stopped working.....totally dead.

So I stripped it off the top of the mill and shock horror.....what a schmozzle.........the motor on the PDB is 12 volts and the supply is 24 volts.........by upping the voltage the idea would be to give the motor more speed and power to push down on the draw bar.....for the short duration it works for.....only now it doesn't work........it failed when going up and left the tool locked in the spindle.

There is a capacitor on the input lines to the PDB to absorb some of the voltage surge, but as capacitors can instantly charge up it's not much use without a resistor in the line too.

If the motor has burned out, I wonder how/why..... it's only been used for a couple of cycles as I'm still not making chips, just doing a bit of practice G coding........it's only cycled on and off for approx 20-30 times in the last 3 months.

This will be a case for Skyfire and Co to handle as it's under warranty and I don't want to mess with the insides of the thruster mechanism to see what's gone wrong.

In the meantime I'll have to rig up a manual jury mechanism to get the tools in and out......and there's no way I'm going for an air solution......ever.
Ian.

I got the second spindle and driver but will delay the install to when all wilk run smooth and clean ,
Concerning your electric PdB Defeng told me that he will not standardized it possibly because he found tht it's not a good long term solution compare to air PdB , maybe don't know .
In my opinion air PDB is the choice as pretty every cnc mill equipped work with

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[jips]

Something not right with that wiring diagram, check for sure where that Ground wire is going to on the Transformer, and how many wires are on the input side of the Transformer

My mistake I did it wrong ! This is the good with photos :







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[handlewanker]

Hi.......yes I agree the air is a good idea, but not my cup of tea, however I might have to go down that path a way if all else fails.....redesigning something is time and labour intensive.

The current electric PDB may not be as satisfactory as I thought it would be if the reliability factor is short lived.....I'll have to see what Defeng has to say.

There is a linear actuator on EBAY going for A$59 rated at 24 volts, 20mm stroke and 600 kg force.....if all else fails I might try a redesign myself as most of the parts for the fitting are already made, and I really need to be able to get the pulleys and belts off without a hassle.

Ahhhhha....you have the 3 phase driver for the high speed spindle already....is it installed and wired in the cabinet and connected to the 2 way switch?

BTW......best of luck when you come to do the change over from the mill spindle to the high speed spindle.........it's not going to be easy.
Ian.

[skillalot]

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that has nothing to do with input power to your drive!

[jips]

Hi.......yes I agree the air is a good idea, but not my cup of tea, however I might have to go down that path a way if all else fails.....redesigning something is time and labour intensive.

The current electric PDB may not be as satisfactory as I thought it would be if the reliability factor is short lived.....I'll have to see what Defeng has to say.

There is a linear actuator on EBAY going for A$59 rated at 24 volts, 20mm stroke and 600 kg force.....if all else fails I might try a redesign myself as most of the parts for the fitting are already made, and I really need to be able to get the pulleys and belts off without a hassle.

Ahhhhha....you have the 3 phase driver for the high speed spindle already....is it installed and wired in the cabinet and connected to the 2 way switch?

BTW......best of luck when you come to do the change over from the mill spindle to the high speed spindle.........it's not going to be easy.
Ian.

I think to install a dedicated spindle mount on one side of the spindle casting like we see on svm1 and just put the high speed spindle in the mount when needed to not overweight the z axis all time if i choose to let it in the mount just a stop pin on the mounting bracket and spindle will always be set up same in Z with quick connector on power wire to easy plug and use , simple way to do imo

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[ihavenofish]

that has nothing to do with input power to your drive!

the rule is generally 2/3 x the ratings. so 14a. 20a is overkill with a quality linear supply. but nothing wrong with overkill.

on switching supplies however, you want a lot of overhead, because they can experience extreme voltage drops when fully loaded. so if they claim 20a, you assume 10a. some of the better brands give a more accurate rating, but the typical cheap supply from ebay is nowhere near.

[handlewanker]

I think to install a dedicated spindle mount on one side of the spindle casting like we see on svm1 and just put the high speed spindle in the mount when needed to not overweight the z axis all time if i choose to let it in the mount just a stop pin on the mounting bracket and spindle will always be set up same in Z with quick connector on power wire to easy plug and use , simple way to do imo

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Hi, yes that is one solution that could work.....you'd lose table work area in the X axis as the spindle can't go all the way to the right, but some compromise is acceptable if the job is not too big.

If you wanted to run a 4th axis you'd have to have the headstock on the right side to allow for the off centre position of the spindle.so you can get the full table movement.

A heavier gas strut would help too.
Ian.

[mactec54]

Why in earth would you need 48V 20Amps to run a machine with 3 steppermotors???

Each Drive can draw upto 7A as rated for 7A x3+21A Plus the draw from the other low voltage hardware in the system, 20A is quite normal for a system like this, they are not normal stepper motors, they are high torque 3 phase steppers with a closed loop, Encoder attached

[skillalot]

You can't just take all the amps on the drives together. It doesn't work like that.

Steppermotors perform best at high voltage, and mostly the maximum voltage is the maximum voltage the driver can handle. Higher voltage means more torque at higher rpm's.
You need to look at the voltage of the motor, and not the actual voltage used on the driver.
The rated voltage for most motors is between 2-5volts.

I don't know the specs of the motor used here, so this ia a different example:

Assuming 5V rated voltage and a 4.5Nm motor with 4.2A per phase.
Power per Coil = 5V x 4.2A = 21W
Total power per motor = 21 x 2 = 42W.
This is without any switching losses, line losses, efficiency of the driver etc., So normally you will do that times 2 just to be sure.
In this case 3 motors would be 42 x 2 x 3 = 252Watt

But again, I don't know the specs of the motors used here.
But my feeling says 20amps is way too much.

[tmarks11]

....now my electric power draw bar has stopped working.....totally dead.......and there's no way I'm going for an air solution......ever.

Concerning your electric PdB Defeng told me that he will not standardized it possibly because he found tht it's not a good long term solution compare to air PdB...

There is a linear actuator on EBAY going for A$59 rated at 24 volts, 20mm stroke and 600 kg force.....if all else fails I might try a redesign myself as most of the parts for the fitting are already made, and I really need to be able to get the pulleys and belts off without a hassle.

Do you recall what the definition of insanity is? Doing the same thing repeatedly, expecting different results.

I would like to draw your attention to at least 100 posts in this thread where people tried to convince you that there is a good reason to use a pneumatic power draw bar.

If you are still really convinced that you want an electric PDB, then you should really take a look at the one Ray designed for the Novakon. His uses a small UPS style lead acid battery to ensure the motor has enough current to tighten and loosen the power draw bar.

[jips]

You can't just take all the amps on the drives together. It doesn't work like that.

Steppermotors perform best at high voltage, and mostly the maximum voltage is the maximum voltage the driver can handle. Higher voltage means more torque at higher rpm's.
You need to look at the voltage of the motor, and not the actual voltage used on the driver.
The rated voltage for most motors is between 2-5volts.

I don't know the specs of the motor used here, so this ia a different example:

Assuming 5V rated voltage and a 4.5Nm motor with 4.2A per phase.
Power per Coil = 5V x 4.2A = 21W
Total power per motor = 21 x 2 = 42W.
This is without any switching losses, line losses, efficiency of the driver etc., So normally you will do that times 2 just to be sure.
In this case 3 motors would be 42 x 2 x 3 = 252Watt

But again, I don't know the specs of the motors used here.
But my feeling says 20amps is way too much.

3A 2n.m

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[mactec54]

You can't just take all the amps on the drives together. It doesn't work like that.

Steppermotors perform best at high voltage, and mostly the maximum voltage is the maximum voltage the driver can handle. Higher voltage means more torque at higher rpm's.
You need to look at the voltage of the motor, and not the actual voltage used on the driver.
The rated voltage for most motors is between 2-5volts.

I don't know the specs of the motor used here, so this ia a different example:

Assuming 5V rated voltage and a 4.5Nm motor with 4.2A per phase.
Power per Coil = 5V x 4.2A = 21W
Total power per motor = 21 x 2 = 42W.
This is without any switching losses, line losses, efficiency of the driver etc., So normally you will do that times 2 just to be sure.
In this case 3 motors would be 42 x 2 x 3 = 252Watt

But again, I don't know the specs of the motors used here.
But my feeling says 20amps is way too much.

Just look at the Transformer, this is not a 10A Transformer, look at the size of the wires, there are many things that say it's a high Amp output transformer, if he could get a better photo of the label on the transformer we would no for sure what it is

[mactec54]

jips

In the cabinet is there a central Ground Point where Ground wires are connected to a Ground post, a Photo of this would help

[jips]

jips

In the cabinet is there a central Ground Point where Ground wires are connected to a Ground post, a Photo of this would help

Do it immediately wait a minute

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[jips]

Just look at the Transformer, this is not a 10A Transformer, look at the size of the wires, there are many things that say it's a high Amp output transformer, if he could get a better photo of the label on the transformer we would no for sure what it is

I made a translate of the chinese sign
Specs in pdf says 400w for the toroidal


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