The shark pro stepper drive motors are 24 volt. Since there are three of them the potential voltage required would be 72
But the power supply appears to be just 24 volts.
Granted, it is unlikely that all three motors
Would be simultaneously running flat out to demand ghat much voltage,shouldn't there be some cushion? I'm wondering if swapping out the provided power supply with one rated for,say, 36 volts wouldn't provide that cushion and improve performance...On the Vectric forum I've seen posts complaining that the Shark seemed underpowered, had to be driven at reduced FR, required very shallow cuts, all indicative of needing a skoach more power. I assume that a larger power supply would not fry any motor because the motors wouldn't draw more than their rated capacity, am I wrong in that?
Shark Underpowered?
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spinningwood
- Posts: 191
- Joined: Wed Aug 04, 2010 11:28 am
Re: Shark Underpowered?
I'm not an electrical engineer and I haven't run down to check on my shark power supply, but I would be amazed if the motors were wired in series (voltage sums) instead of being wired in parallel (current sums).
Rather than worrying about voltage, it seems to me you should be considering the amount of current the the power supply can deliver and the current draw of the motors.
I don't recall reading any complaints on the Vectric forum about the shark being underpowered. Maybe you could provide a link. Maybe you misinterpreted what you read?
Ed
Rather than worrying about voltage, it seems to me you should be considering the amount of current the the power supply can deliver and the current draw of the motors.
I don't recall reading any complaints on the Vectric forum about the shark being underpowered. Maybe you could provide a link. Maybe you misinterpreted what you read?
Ed
Re: Shark Underpowered?
Well, I'm not an electrical engineer, either, but the power source is marked "24 volts" so to my admittedly uneducated mind would seem that however they are wired, there are three motors demanding 24 volts each. That's a total of 72 volts looking to be fed from one 24 volt power source. Other sources I consulted in trying to learn more about cnc related manufacturer's suggestions that the power supply be about 60% of the total system demand. Do you think more power would hurt the shark's performance?
Here is a link(if I'm doing it right) to the vectric formum post I alluded to: http://www.vectric.com/forum/viewtopic.php?f=4&t=6874
Here is a link(if I'm doing it right) to the vectric formum post I alluded to: http://www.vectric.com/forum/viewtopic.php?f=4&t=6874
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spinningwood
- Posts: 191
- Joined: Wed Aug 04, 2010 11:28 am
Re: Shark Underpowered?
If you are in the US then you most likely have 110v to 120v supply. Your refigerator, lights, computers and probably lots of other stuff are all on at the same time. Are you worried that you are sucking too many volts out of the house with all those 110v things running at the same time? Of course not. It's the amps that count. Pull too many amps out of a circuit and the breaker cuts the power. You can plug in as many 110v electrical things as you have outlets as long as the total current drawn by them does not exceed the limit for the circuit.
Which is more dangerous? A 50,000 volt shock or a 12 volt shock. Without knowing the power you can't say. When you get a static shock in the winter you are taking a lot of volts but very little power so it doesn't kill you. If you were to hook some battery cables up to your car battery and to yourself the 12 volts at high amperage might kill you.
It's not the voltage that matters.
As far as the link to the vectric forum thread, nobody presented enough information to really arrive at any kind of conclusion about anything.
One guy says "My machine does not respond well if I go faster than 70% feed rate and I use the lowest setting (1-2) for the router speed". He doesn't say what his feed rate was or what he was cutting or with what kind of cutter. 70% FRO is is going to be a lot different if the toolpath was created at 100ipm versus 10ipm. Router speed of 1 or 2 may or may not be appropriate given the material and cutter. You really can't tell if the problems he felt he was having was a function of the machine not working right or his lack of understanding of how to properly operate it.
I'm not saying the shark is perfect for every job or that there haven't been people that have had real problems with their shark. I think you are worrying about the wrong stuff though. How about sharing a little info on the kinds of jobs you want to run. Someone may have experience with that kind of work and be able to give you some direct feedback on how the shark performed.
Ed
Which is more dangerous? A 50,000 volt shock or a 12 volt shock. Without knowing the power you can't say. When you get a static shock in the winter you are taking a lot of volts but very little power so it doesn't kill you. If you were to hook some battery cables up to your car battery and to yourself the 12 volts at high amperage might kill you.
It's not the voltage that matters.
As far as the link to the vectric forum thread, nobody presented enough information to really arrive at any kind of conclusion about anything.
One guy says "My machine does not respond well if I go faster than 70% feed rate and I use the lowest setting (1-2) for the router speed". He doesn't say what his feed rate was or what he was cutting or with what kind of cutter. 70% FRO is is going to be a lot different if the toolpath was created at 100ipm versus 10ipm. Router speed of 1 or 2 may or may not be appropriate given the material and cutter. You really can't tell if the problems he felt he was having was a function of the machine not working right or his lack of understanding of how to properly operate it.
I'm not saying the shark is perfect for every job or that there haven't been people that have had real problems with their shark. I think you are worrying about the wrong stuff though. How about sharing a little info on the kinds of jobs you want to run. Someone may have experience with that kind of work and be able to give you some direct feedback on how the shark performed.
Ed
Re: Shark Underpowered?
Just to put in my 2 cents on the voltage and steppers motors. The controller is not rated for 36V if you put it on there you will blow the controller. The next point is these motors are not so much as the voltage as they are current. Stepper motors of the Nemi 23 size (which is what the shark uses) are typically 3-5 volt motors. You can’t think of these steppers like a fan motor for instance that you just plug in a voltage and it will work. If you do that with stepper motors in the voltage range you will get nothing. They are given voltage in pulses streams that determine their direction and speed.
I could run this controller on a 12V -24V and you would not notice really any difference in performance since the motors are energized at a much lower voltage range. 24 V supply is generally a standard supply voltage so we are conforming to that. On larger systems (4x4 or 4x8) tables they run higher voltages to energize the coils faster but the steppers are designed take that (nemi 34+) Then you can get into a whole host of other issues including drivers and controllers that are doing better harmonic dampening ect, but you will pay($) for it.
Tim
I could run this controller on a 12V -24V and you would not notice really any difference in performance since the motors are energized at a much lower voltage range. 24 V supply is generally a standard supply voltage so we are conforming to that. On larger systems (4x4 or 4x8) tables they run higher voltages to energize the coils faster but the steppers are designed take that (nemi 34+) Then you can get into a whole host of other issues including drivers and controllers that are doing better harmonic dampening ect, but you will pay($) for it.
Tim