milling machine needs more power!
so, im planning on converting my milling machine to CNC, but ive never been able to use the top 3 speeds on it because it wont turn on.
its belt driven, and has 3 pulleys with 4 positions on them, for a total of 12 speeds. i cant use the fastest 3 because when the machine turns on, it draws a lot of current, and trips my breaker every time. it starts to turn and ALMOST starts, but doesnt quite make it. if i use the slower speeds, it turns on fine (after a bit of light-dimming).
the motor is a 2.0HP single-phase induction motor. it uses a 150uf and 20uf cap for starting. i could figure out how its all wired, i just need to take it apart again, which is easy.
the obvious thing to do would be to install a 20amp line, or wire it for 220, and install a 220 line. well, those arent options for me. i cannot mess with the electricity in the house. its not my house and my landlord wont let me do this.
can i add a bigger cap, or more caps to make it start up? once its running, it doesnt draw all that much current, its just when it starts up, it takes a lot of juice. or maybe some kinda slow-start thing like we do with amps? any help would be appreciated!
edit:
i can get diagrams, pictures, and more data if needed...
so, im planning on converting my milling machine to CNC, but ive never been able to use the top 3 speeds on it because it wont turn on.
its belt driven, and has 3 pulleys with 4 positions on them, for a total of 12 speeds. i cant use the fastest 3 because when the machine turns on, it draws a lot of current, and trips my breaker every time. it starts to turn and ALMOST starts, but doesnt quite make it. if i use the slower speeds, it turns on fine (after a bit of light-dimming).
the motor is a 2.0HP single-phase induction motor. it uses a 150uf and 20uf cap for starting. i could figure out how its all wired, i just need to take it apart again, which is easy.
the obvious thing to do would be to install a 20amp line, or wire it for 220, and install a 220 line. well, those arent options for me. i cannot mess with the electricity in the house. its not my house and my landlord wont let me do this.
can i add a bigger cap, or more caps to make it start up? once its running, it doesnt draw all that much current, its just when it starts up, it takes a lot of juice. or maybe some kinda slow-start thing like we do with amps? any help would be appreciated!
edit:
i can get diagrams, pictures, and more data if needed...
You may want to try a UPS (Uninterruptible Power Supply) rated for the max draw of your device, and then put a time delay on the mains connection of the UPS. What this would do is to start the motor under UPS power, then once the motor is started (and the amperage has dropped to normal), you restore power to the UPS, which then provides the running draw you need, while trickle charging the batteries. I used this kind of set-up in an Apartment in a similiar setup. I only had a 15 amp circuit to use, but I was running a Salt Water Reef Tank with 1200 watts of HID lighting. While the amperage of the circuit was roughly around 13 when everything was up and running, it spiked to 28 or so (Tar ballasts are notoriously inefficient) when everything was igniting. Please note: I make no claims that this is SAFE, or anything, it is just what I did in a similiar scenario, and overloading your electrical wiring could cause a fire.
hum, thats a decent idea...
the problem is, if im pulling more than 15 amps, which is tripping the breaker, i would need one HELL of a UPS. that would be at least a 2kva or so, which would be a few hundred dollars...
i couldnt use like a 500va for a few seconds or so? i would have to have a larger one?
the problem is, if im pulling more than 15 amps, which is tripping the breaker, i would need one HELL of a UPS. that would be at least a 2kva or so, which would be a few hundred dollars...
i couldnt use like a 500va for a few seconds or so? i would have to have a larger one?
The 220 option is the way to go. I re-wired a table saw this way and the performance difference is night and day. It's safer to operate as well. If the owner won't let you add a 220 outlet then you could make a custom extension cord to use the dryer outlet. First rewire the milling machine and put on a 220 plug. Then build the extension cord with a 220 receptacle on one end to match the plug on the machine. On the other end put a dryer plug. DON'T MIX 220 AND 110 CONNECTORS.
A word of warning: dryers usually run on a high amperage circuit like 40 amps. If there's a problem, and if your machine is supposed to be used with a 15 or 20 amp 220V circuit and breaker, then something could really get wrecked before a 40 amp breaker goes.
It's chance I decided to take years ago and I have been fine.
GL
A word of warning: dryers usually run on a high amperage circuit like 40 amps. If there's a problem, and if your machine is supposed to be used with a 15 or 20 amp 220V circuit and breaker, then something could really get wrecked before a 40 amp breaker goes.
It's chance I decided to take years ago and I have been fine.
GL
I am familiar with single phase mills and will only say that when we talk about single phase, we are never even thinking about 110VAC.
The extension cord to 220V at the stove or dryer is the hot setup. Fuse both sides (the two black wires) with ~15A on #12. If the run is longer than 30', jump to #10.
The extension cord to 220V at the stove or dryer is the hot setup. Fuse both sides (the two black wires) with ~15A on #12. If the run is longer than 30', jump to #10.
It's good to see that others have done the same. My Extension cord is #10 at about 30ft. I used the dryewr as the likely connection because it's probably physically closer to the milling machine.
I presume that you offered to have an electrician come in and professionally add a 220 circuit at your expense. The owner is sort of dim to turn down an offer like that since it would add value to his property!!!!!.
GL
I presume that you offered to have an electrician come in and professionally add a 220 circuit at your expense. The owner is sort of dim to turn down an offer like that since it would add value to his property!!!!!.
GL
wow, its like no one read my post...
i CANNOT do what you guys are suggesting, period. running a 220 cord is a possibility, but the closest outlet would be around 30-50 feet away, and through many walls and up a level. it would be easier to add a 220 line.
secondly, my landlord (and actually my roommate, same guy) will not allow the modifications for whatever reason. so, its NOT an option. i need to do it another way.
i CANNOT do what you guys are suggesting, period. running a 220 cord is a possibility, but the closest outlet would be around 30-50 feet away, and through many walls and up a level. it would be easier to add a 220 line.
secondly, my landlord (and actually my roommate, same guy) will not allow the modifications for whatever reason. so, its NOT an option. i need to do it another way.
We are not talking about any modifications at all. We are talking about an extension cord. I would have to assume that there are doors and hallways between the location of your mill and the dryer or stove. You can go through the walls if you must... but the doorways might be less destructive.
poobah said:We are not talking about any modifications at all. We are talking about an extension cord. I would have to assume that there are doors and hallways between the location of your mill and the dryer or stove. You can go through the walls if you must... but the doorways might be less destructive.
well, the machine is in my basement, and the washer/dryer and stove are all on the opposite side of the house, up a level. i COULD run an extenstion cord, but it would be through 3 rooms, then up a flight of stairs, through 3 more rooms, and then to the outlet.
i guess it could work, but i was thinking maybe of upping the cap values or something. the UPS idea is nice too. thats all. if i MUST use a 220 outlet or something, i guess i could find a way. but i use this machine a LOT and id rather not have to hook up 100ft of extension cord to use it every time.
gl said:
very very helpful. thanks for the post. i really appreciate it. an asset to the DIY community!
OK... so that's a hassle then... understood.
Upping the caps won't help... they are there to create a second phase... not start up power.
The UPS will cost you at least $2000... plus you need a 4kW ups to start a 2kW motor.
Now... this sounds crazy; take a spool or a pulley or something; and wind 4 ft of rope around your spindle. Pull it like an old fashioned lawnmower and THEN throw the switch. It's up to you to do this safely.
You can also put a centrifugal clutch on the motor spindle. This would allow the motor to spin-up to a good speed before trying to power the spindle and such. Here's a link:
http://www.blm-cm.com
There are cheaper models for mini bikes and go-karts you might be able to adapt.
The cheapest is to wire it in for 40 Amps... since you're in the basement it's a breeze. Do all of it yourself right up to breaker box in 3/4" conduit, and then have an electrician make the final hookup ($100?). Convince your landlord (Felix Ungar... not a tool guy) that a 220-240 outlet in the basement is a plus... because that's the truth.
Good luck,
BTW, the extension cord won't set you back much... and someone might get tired of seeing laying on the stairs etc... (war of gentle attrition).
Upping the caps won't help... they are there to create a second phase... not start up power.
The UPS will cost you at least $2000... plus you need a 4kW ups to start a 2kW motor.
Now... this sounds crazy; take a spool or a pulley or something; and wind 4 ft of rope around your spindle. Pull it like an old fashioned lawnmower and THEN throw the switch. It's up to you to do this safely.
You can also put a centrifugal clutch on the motor spindle. This would allow the motor to spin-up to a good speed before trying to power the spindle and such. Here's a link:
http://www.blm-cm.com
There are cheaper models for mini bikes and go-karts you might be able to adapt.
The cheapest is to wire it in for 40 Amps... since you're in the basement it's a breeze. Do all of it yourself right up to breaker box in 3/4" conduit, and then have an electrician make the final hookup ($100?). Convince your landlord (Felix Ungar... not a tool guy) that a 220-240 outlet in the basement is a plus... because that's the truth.
Good luck,
BTW, the extension cord won't set you back much... and someone might get tired of seeing laying on the stairs etc... (war of gentle attrition).
well, thanks for the info.
i DID fine a 2kva ups for around $250. shipping would definately add some money of course.
even though the machine is in my basement, its not as easy as you would think to wire it for a bigger circuit. its actually LONGER away than running an extension cord. the circuit breaker is on the outside of my house, to the back of the washer/dryer. so, its not as cake as you might think. PLUS, the room that the machine is in is the ONLY unfinished part of the basement, the rest is completely finished. so, not very easy. plus, i cant do it, i dont have permission
the pull-start is an interesting idea. it would take a bit of practice to get it to work though.
i wouldnt be able to permanently run the extension cord inside because not only would my roommate put a stop to it, but so would i. my house is relatively nice, and we like to keep it clean and picked up. an extension cord running through 5 rooms wouldnt be tolerated.
ill have to think it over a bit. i always thought the caps on the motor were for startup? arent they ac motor start caps?
i DID fine a 2kva ups for around $250. shipping would definately add some money of course.
even though the machine is in my basement, its not as easy as you would think to wire it for a bigger circuit. its actually LONGER away than running an extension cord. the circuit breaker is on the outside of my house, to the back of the washer/dryer. so, its not as cake as you might think. PLUS, the room that the machine is in is the ONLY unfinished part of the basement, the rest is completely finished. so, not very easy. plus, i cant do it, i dont have permission
the pull-start is an interesting idea. it would take a bit of practice to get it to work though.
i wouldnt be able to permanently run the extension cord inside because not only would my roommate put a stop to it, but so would i. my house is relatively nice, and we like to keep it clean and picked up. an extension cord running through 5 rooms wouldnt be tolerated.
ill have to think it over a bit. i always thought the caps on the motor were for startup? arent they ac motor start caps?
They call them start caps... but that is mis-leading They are caps to provide a artificial phase so the motor will turn in the correct direction AND actually start moving in ANY direction at all. They don't give you a "start up" boost.
Don't be fooled by the "specs" on UPS... they are BS and won't start your motor. I have much experience with many different UPS & invertors. No one will talk about motor starting... don't bother. This was for the World Health Organization trying to make vaccine refridgerators function from a low cost invertor... again, don't bother.
Try the rope thing OR the "centrifugal clutch"... this is all that is open to you. Except for some proper wiring... sorry, you have physics in your way...
Don't be fooled by the "specs" on UPS... they are BS and won't start your motor. I have much experience with many different UPS & invertors. No one will talk about motor starting... don't bother. This was for the World Health Organization trying to make vaccine refridgerators function from a low cost invertor... again, don't bother.
Try the rope thing OR the "centrifugal clutch"... this is all that is open to you. Except for some proper wiring... sorry, you have physics in your way...
Something's bothering me after reading this entire thread, and it could simply be my lack of knowledge with milling machines, but here goes:
On the three highest settings, the motor is stalling, which means, its not getting enough current to start the thing spinning. What this says to me is there's a problem somewhere, and I don't mean the electrical system. If it can't get enough torque to start the blade or bit spinning, its not going to have much torque once it gets going either. I'd look more at figuring out why it needs so much torque to start at the highest speeds, rather than trying to accomodate the higher power draw.
This is assuming its similar in design to something like my drill press, it spins freely on all of its settings, and has high torque, regardless of the speed settings. (Yes, I understand they're only similar, but work with me on this) Are you trying to spin a very large bit at these speeds? Why does it take so much torque to start the thing? Does it bog down easily? Are the highest speed settings towards the top/end of the spindles? If so, maybe you're over-tensioning the belt and its bending the spindles causing the higher torque requirements.
These are my thoughts, based upon a flimsy knowledge of milling machines. Feel free to tell me where I'm off my rocker.
On the three highest settings, the motor is stalling, which means, its not getting enough current to start the thing spinning. What this says to me is there's a problem somewhere, and I don't mean the electrical system. If it can't get enough torque to start the blade or bit spinning, its not going to have much torque once it gets going either. I'd look more at figuring out why it needs so much torque to start at the highest speeds, rather than trying to accomodate the higher power draw.
This is assuming its similar in design to something like my drill press, it spins freely on all of its settings, and has high torque, regardless of the speed settings. (Yes, I understand they're only similar, but work with me on this) Are you trying to spin a very large bit at these speeds? Why does it take so much torque to start the thing? Does it bog down easily? Are the highest speed settings towards the top/end of the spindles? If so, maybe you're over-tensioning the belt and its bending the spindles causing the higher torque requirements.
These are my thoughts, based upon a flimsy knowledge of milling machines. Feel free to tell me where I'm off my rocker.
cowanrg
What brand of mill is it? Is it possible that the motor has been replaced with a smaller HP motor? I spent thousands of hours running all types of mills. Do you have an amp clamp to check the current draw on the lower speeds?
Most of the Bridgeports I ran had 5 HP three phase motors on them.
What brand of mill is it? Is it possible that the motor has been replaced with a smaller HP motor? I spent thousands of hours running all types of mills. Do you have an amp clamp to check the current draw on the lower speeds?
Most of the Bridgeports I ran had 5 HP three phase motors on them.
Bridgeport Series II Special was 5HP
Series I step belts were 1 or 1-1/2.
That being said, I think the solution would be to add an AC variable drive to the existing motor. This would allow you to start the machine in the high speed belt position and increase the AC drive to max.
There's a motor shop in your community somewhere. They typically have somebody with a brain and a shelf with used **** that they could sell you.
Series I step belts were 1 or 1-1/2.
That being said, I think the solution would be to add an AC variable drive to the existing motor. This would allow you to start the machine in the high speed belt position and increase the AC drive to max.
There's a motor shop in your community somewhere. They typically have somebody with a brain and a shelf with used **** that they could sell you.
Cold oil?
Hmmm. I had trouble with my mill a few weeks ago. It's only a toy mill (compared to a Bridgeport), but I found it had trouble starting on its highest speed, and took a little while to get up to full speed. As I was freezing my nadgers off at the time, I concluded that the oil in the gearbox was cold. Sure enough, when I used the mill the next day (and had turned the heating on), it ran happily immediately.
Hmmm. I had trouble with my mill a few weeks ago. It's only a toy mill (compared to a Bridgeport), but I found it had trouble starting on its highest speed, and took a little while to get up to full speed. As I was freezing my nadgers off at the time, I concluded that the oil in the gearbox was cold. Sure enough, when I used the mill the next day (and had turned the heating on), it ran happily immediately.
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