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Arboga mill converted to VFD control (pictures)
Now this 3 phase mill can run from single phase (regular 220v plug),
it stops in 0.5 seconds thanks to electric braking, and it also reverses, which is something it was not capable of before. In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). All of the above make this machine more desirable. http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/ |
Arboga mill converted to VFD control (pictures)
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Arboga mill converted to VFD control (pictures)
On 2009-08-30, Charles U Farley wrote:
Ignoramus7041 wrote in news:- : http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/ Ahhhh! Ventilated electronics enclosure mounted below the table of a metalworking machine tool. runs and hides Yes, good point, I was going to put a cover above it. Have not gotten to it yet. i |
Arboga mill converted to VFD control (pictures)
Do you know if the company is still in business for parts?
My Arboga radial arm drill broke the power down while doing a 3" hole this summer. Its on my winter repair list. Karl |
Arboga mill converted to VFD control (pictures)
On 2009-08-30, Karl Townsend wrote:
Do you know if the company is still in business for parts? My Arboga radial arm drill broke the power down while doing a 3" hole this summer. Its on my winter repair list. Do you know what broke exactly? I looked and could not find their website, I suspect that they were bought out by Wilton (WMH tool group). i |
Arboga mill converted to VFD control (pictures)
On Sun, 30 Aug 2009 16:20:51 -0500, Ignoramus7041
wrote: Now this 3 phase mill can run from single phase (regular 220v plug), it stops in 0.5 seconds thanks to electric braking, and it also reverses, which is something it was not capable of before. In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). All of the above make this machine more desirable. http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/ Seriously big pending ****up. That VFD needs to go on the BACKSIDE of the mill column. You are going to get chips down into the top of it in its present location and all the magic smoke is going to come out of it. At the very very least..put a horizontal thin plate aprox 1" above the upper vent grid to protect it from **** going down the grid. Trust me on this. It WILL happen. Gunner Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them. |
Arboga mill converted to VFD control (pictures)
On 2009-08-31, Gunner Asch wrote:
On Sun, 30 Aug 2009 16:20:51 -0500, Ignoramus7041 wrote: Now this 3 phase mill can run from single phase (regular 220v plug), it stops in 0.5 seconds thanks to electric braking, and it also reverses, which is something it was not capable of before. In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). All of the above make this machine more desirable. http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/ Seriously big pending ****up. That VFD needs to go on the BACKSIDE of the mill column. You are going to get chips down into the top of it in its present location and all the magic smoke is going to come out of it. At the very very least..put a horizontal thin plate aprox 1" above the upper vent grid to protect it from **** going down the grid. Trust me on this. It WILL happen. Yes, I will put some sort of a thin plate over it asap. Good catch Gunner. I actually thought to do it, then completely forgot. I am reluctant to put it on the back, it will make it hard to program. i |
Arboga mill converted to VFD control (pictures)
Do you know if the company is still in business for parts? My Arboga radial arm drill broke the power down while doing a 3" hole this summer. Its on my winter repair list. Do you know what broke exactly? Nope, I just engaged the power down and it wasn't there any more. Means you got to stand there and push down by hand - sux on a deep large hole. Karl |
Arboga mill converted to VFD control (pictures)
On 2009-08-31, Karl Townsend wrote:
Do you know if the company is still in business for parts? My Arboga radial arm drill broke the power down while doing a 3" hole this summer. Its on my winter repair list. Do you know what broke exactly? Nope, I just engaged the power down and it wasn't there any more. Means you got to stand there and push down by hand - sux on a deep large hole. This makes me hope that it is something simple, some intentional weak link. Maybe there is some roll pin that is purposely made to break under excess load. i |
Arboga mill converted to VFD control (pictures)
Do you know what broke exactly? Nope, I just engaged the power down and it wasn't there any more. Means you got to stand there and push down by hand - sux on a deep large hole. This makes me hope that it is something simple, some intentional weak link. Maybe there is some roll pin that is purposely made to break under excess load. Very likely, being able to talk to somebody that knows this machine or having an assembly drawing would be worth its weight in gold. Karl |
Arboga mill converted to VFD control (pictures)
On Sun, 30 Aug 2009 19:16:19 -0500, Ignoramus7041
wrote: On 2009-08-31, Gunner Asch wrote: On Sun, 30 Aug 2009 16:20:51 -0500, Ignoramus7041 wrote: Now this 3 phase mill can run from single phase (regular 220v plug), it stops in 0.5 seconds thanks to electric braking, and it also reverses, which is something it was not capable of before. In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). All of the above make this machine more desirable. http://yabe.algebra.com/~ichudov/mis...25-Mill-Drill/ Seriously big pending ****up. That VFD needs to go on the BACKSIDE of the mill column. You are going to get chips down into the top of it in its present location and all the magic smoke is going to come out of it. At the very very least..put a horizontal thin plate aprox 1" above the upper vent grid to protect it from **** going down the grid. Trust me on this. It WILL happen. Yes, I will put some sort of a thin plate over it asap. Good catch Gunner. I actually thought to do it, then completely forgot. I am reluctant to put it on the back, it will make it hard to program. i You already have a "remote control" that sets forward/off/reverse and speed, right? A simple Form C toggle switch and a pot in a tiny little box mounted somewhere on the face of the machine. Right? Ive got a number of mills with the VFD mounted in boxes on the wall Behind the mill, with the simple control device mounted on the head. Its not rocket science, and it makes the machine safe, secure and unlikely for the magic smoke to come out. And its quite easy to simply change the wiring on the existing power switch to run directly to the VFD and the head switch (I didnt check) control the VFD, rather than the 3ph power directly. Gunner Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them. |
Arboga mill converted to VFD control (pictures)
On 2009-08-31, Gunner Asch wrote:
You already have a "remote control" that sets forward/off/reverse and speed, right? Yes A simple Form C toggle switch and a pot in a tiny little box mounted somewhere on the face of the machine. Right? Exactly. Ive got a number of mills with the VFD mounted in boxes on the wall Behind the mill, with the simple control device mounted on the head. Its not rocket science, and it makes the machine safe, secure and unlikely for the magic smoke to come out. And its quite easy to simply change the wiring on the existing power switch to run directly to the VFD and the head switch (I didnt check) control the VFD, rather than the 3ph power directly. Well, yes, but it is an on/off switch, and I need a forward/reverse switch. Anyway, I did put a cover over the top of the VFD last night, it should be fine as is. i |
Arboga mill converted to VFD control (pictures)
In article ,
Ignoramus25738 wrote: On 2009-08-31, Gunner Asch wrote: You already have a "remote control" that sets forward/off/reverse and speed, right? Yes A simple Form C toggle switch and a pot in a tiny little box mounted somewhere on the face of the machine. Right? Exactly. Ive got a number of mills with the VFD mounted in boxes on the wall Behind the mill, with the simple control device mounted on the head. Its not rocket science, and it makes the machine safe, secure and unlikely for the magic smoke to come out. And its quite easy to simply change the wiring on the existing power switch to run directly to the VFD and the head switch (I didn't check) control the VFD, rather than the 3ph power directly. Well, yes, but it is an on/off switch, and I need a forward/reverse switch. Anyway, I did put a cover over the top of the VFD last night, it should be fine as is. Chips are far too clever for a simple cover to work for very long, unless the cover is so tight that airflow is blocked. One can cut the leakage rate down with some fine-mesh metal screening, but even that isn't perfect. Real factories often put the VFDs in a closed metal box, precisely to protect the VFD from factory dust, dirt, chips, gasses, et al. And from confused button-pushers, but that's another story. It's easy to build a remote-control box for a VFD, which is mounted up high on the wall, behind the mill, out of the chip impact zone. Put the VFD's displays at eye height and programming (a rare activity) is easy enough. Joe Gwinn |
Arboga mill converted to VFD control (pictures)
On Mon, 31 Aug 2009 07:12:52 -0500, Ignoramus25738
wrote: On 2009-08-31, Gunner Asch wrote: You already have a "remote control" that sets forward/off/reverse and speed, right? Yes A simple Form C toggle switch and a pot in a tiny little box mounted somewhere on the face of the machine. Right? Exactly. Ive got a number of mills with the VFD mounted in boxes on the wall Behind the mill, with the simple control device mounted on the head. Its not rocket science, and it makes the machine safe, secure and unlikely for the magic smoke to come out. And its quite easy to simply change the wiring on the existing power switch to run directly to the VFD and the head switch (I didnt check) control the VFD, rather than the 3ph power directly. Well, yes, but it is an on/off switch, and I need a forward/reverse switch. Anyway, I did put a cover over the top of the VFD last night, it should be fine as is. i Lets hope so. Though I suspect, based on my years as a machine tool mechanic in commercial machine shops...that it wont blow up until the new owners uses it for more than 30 days...or maybe not. Shrug... Gunner Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them. |
Arboga mill converted to VFD control (pictures)
On Mon, 31 Aug 2009 09:57:31 -0400, Joseph Gwinn
wrote: In article , Ignoramus25738 wrote: On 2009-08-31, Gunner Asch wrote: You already have a "remote control" that sets forward/off/reverse and speed, right? Yes A simple Form C toggle switch and a pot in a tiny little box mounted somewhere on the face of the machine. Right? Exactly. Ive got a number of mills with the VFD mounted in boxes on the wall Behind the mill, with the simple control device mounted on the head. Its not rocket science, and it makes the machine safe, secure and unlikely for the magic smoke to come out. And its quite easy to simply change the wiring on the existing power switch to run directly to the VFD and the head switch (I didn't check) control the VFD, rather than the 3ph power directly. Well, yes, but it is an on/off switch, and I need a forward/reverse switch. Anyway, I did put a cover over the top of the VFD last night, it should be fine as is. Chips are far too clever for a simple cover to work for very long, unless the cover is so tight that airflow is blocked. One can cut the leakage rate down with some fine-mesh metal screening, but even that isn't perfect. Real factories often put the VFDs in a closed metal box, precisely to protect the VFD from factory dust, dirt, chips, gasses, et al. And from confused button-pushers, but that's another story. It's easy to build a remote-control box for a VFD, which is mounted up high on the wall, behind the mill, out of the chip impact zone. Put the VFD's displays at eye height and programming (a rare activity) is easy enough. Joe Gwinn Indeed. Well said. Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them. |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? Something I could pick up at Radio Shack or do I need to order on line? Under what section of the manual would you go looking for specs if it's something that varies by manufacturer and model? I only read enough of the manual to get my mill up and running so I could play with it. Now that I've had it for several months, it's time to make improvements. RWL |
Was- Arboga mill converted to VFD - now Q about pot & switchesfor VFD
On 2009-09-01, GeoLane at PTD dot NET GeoLane wrote:
In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? Something I could pick up at Radio Shack or do I need to order on line? Under what section of the manual would you go looking for specs if it's something that varies by manufacturer and model? I only read enough of the manual to get my mill up and running so I could play with it. Now that I've had it for several months, it's time to make improvements. Your VFD manual does not seem to say what the rating for the pot should be. Mine said, IIRC, that it should be between 1k and 10k. I used a 1k pot because I have a few of those. 5k should work well. You can call Teco and ask to be sure. If you want a pot and an on-off switch, then you can buy a pot with a built in switch, those are widely available. They have two contacts for a switch and three for a pot, usually they click and turn off when fully turned counterclockwise. So you can wire that switch to turn off the current when the switch is off, and turn on and ramp up the frequency as you turn the knob clockwise. Now if you want a pot and a forward/off/reverse switch, then you need to have them separately, pretty much. It is really up to you as to what you want, for instance whether you want to power tap on the mill. Radio Shack could be pricey, but the easiest option of all. Most likely you need a 5k pot. i |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On Mon, 31 Aug 2009 21:48:17 -0400, GeoLane at PTD dot NET GeoLane at
PTD dot NET wrote: In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? Something I could pick up at Radio Shack or do I need to order on line? Under what section of the manual would you go looking for specs if it's something that varies by manufacturer and model? I only read enough of the manual to get my mill up and running so I could play with it. Now that I've had it for several months, it's time to make improvements. RWL Look in the wiring diagrams and it should show you what value the pot is supposed to be. Generally....0-5k...some are 0-10k, others are different. This is not something to guess at. If you do..you will never get it going fast enough...or ever get it going, or ever get it going slow enough..... G Gunner Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them. |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On 1 Sep 2009 06:09:17 GMT, "DoN. Nichols" wrote:
On 2009-09-01, GeoLane at PTD dot NET GeoLane wrote: In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? Something I could pick up at Radio Shack or do I need to order on line? Under what section of the manual would you go looking for specs if it's something that varies by manufacturer and model? I only read enough of the manual to get my mill up and running so I could play with it. Now that I've had it for several months, it's time to make improvements. Typical pot is a 5K or 10K linear pot with a 2W power rating. As for the switch -- make it a SPDTCO (Single Pole Single Throws Center Off) switch so you can use it to select forward stop or reverse. (It might be good to have one of the locking toggles with the pull-to-release handles, so you can't accidentally go from forward to reverse when you really want to stop. There should be wiring diagrams for how to connect such switches, as well as ones for using three push buttons (forward, reverse, and stop). For the latter, a red mushroom actuator for ths top switch with a locking mode so you have to twist it or pull it to reset the stop. That way, you just bring your hand up and slap it to stop in an emergency. Enjoy, DoN. Very well said! Gunner Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them. |
Was- Arboga mill converted to VFD - now Q about pot & switchesfor VFD
On 2009-09-01, Gunner Asch wrote:
On 1 Sep 2009 06:09:17 GMT, "DoN. Nichols" wrote: On 2009-09-01, GeoLane at PTD dot NET GeoLane wrote: In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? Something I could pick up at Radio Shack or do I need to order on line? Under what section of the manual would you go looking for specs if it's something that varies by manufacturer and model? I only read enough of the manual to get my mill up and running so I could play with it. Now that I've had it for several months, it's time to make improvements. Typical pot is a 5K or 10K linear pot with a 2W power rating. As for the switch -- make it a SPDTCO (Single Pole Single Throws Did you mean double throw? Got a source for those? i Center Off) switch so you can use it to select forward stop or reverse. (It might be good to have one of the locking toggles with the pull-to-release handles, so you can't accidentally go from forward to reverse when you really want to stop. There should be wiring diagrams for how to connect such switches, as well as ones for using three push buttons (forward, reverse, and stop). For the latter, a red mushroom actuator for ths top switch with a locking mode so you have to twist it or pull it to reset the stop. That way, you just bring your hand up and slap it to stop in an emergency. Enjoy, DoN. Very well said! Gunner Whenever a Liberal utters the term "Common Sense approach"....grab your wallet, your ass, and your guns because the sombitch is about to do something damned nasty to all three of them. |
Was- Arboga mill converted to VFD - now Q about pot & switchesfor VFD
The switch 's resistance should be much less than the input impedance,
but big enough so as not to exceed the limit on current produced by the CC terminal. 5k should most likely work and those are very common pots. I put a 1k pot in my drive the other day and it works great. i On 2009-09-01, DoN. Nichols wrote: On 2009-09-01, Gunner Asch wrote: [ ... ] Look in the wiring diagrams and it should show you what value the pot is supposed to be. Generally....0-5k...some are 0-10k, others are different. Yes -- but these are common ratings. This is not something to guess at. If you do..you will never get it going fast enough...or ever get it going, or ever get it going slow enough..... Hmm ... that effect would be more if it were being wired and used as a rheostat instead of a potentiometer. Normally, the VFD has three pins for use with a pot. One is common ground, one puts out 10V or 5V, and the third connects to the wiper. Usually, the output voltage is capable of sufficient current for 1K, 5K or 10K, and what really matters is the voltage which the wiper returns to the control input, which should cover the same range with any reasonable value of potentiometer. Go really too high, and you are likely to pick up noise which will cause the speed to vary a lot at mid range settings. Go really too low, and the 5V or 10V output can't provide enough current, and the voltage will be too low so you can't get enough speed. But anything from 1K to 10K should be fine -- with values beyond that possibly encountering problems. But it is not a critical value. Enjoy, DoN. |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? RWL Look in the wiring diagrams and it should show you what value the pot is supposed to be. Generally....0-5k...some are 0-10k, others are different. Gunner Thanks Gunner, Iggy, Don I scanned through the manual looking for the wiring diagram and next to the potentiometer it says "10k ?" I"m not sure why the "?" is printed in the book but that's what it says. I looked at the on line listing at Radio Shack - not too pricey, about $3. The only problem is, they only list 0.5W potentiometers and Don had mentioned it ought to be 2 Watts. I looked in the Mouser catalog and I spot two that would probably do the job. One's a high precision single turn pot EUP-1400-10k for $4.15. The other is listed as a 53 series industrial pot with a 25k rotational life expectancy. 785-531C10k for $6.76 Both of these handle 2 watts. It looks like the control switches for my VFD should be momentary switches. RWL |
Was- Arboga mill converted to VFD - now Q about pot & switchesfor VFD
On 2009-09-02, GeoLane at PTD dot NET GeoLane wrote:
I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? RWL Look in the wiring diagrams and it should show you what value the pot is supposed to be. Generally....0-5k...some are 0-10k, others are different. Gunner Thanks Gunner, Iggy, Don I scanned through the manual looking for the wiring diagram and next to the potentiometer it says "10k ?" I"m not sure why the "?" is printed in the book but that's what it says. I looked at the on line listing at Radio Shack - not too pricey, about $3. The only problem is, they only list 0.5W potentiometers and Don had mentioned it ought to be 2 Watts. If the control voltage is 10 volts, then a 10k potentiometer would dissipate 10v*10v/10000ohm = 0.01 watts. You do not need a 2 watt 10k pot. I looked in the Mouser catalog and I spot two that would probably do the job. One's a high precision single turn pot EUP-1400-10k for $4.15. The other is listed as a 53 series industrial pot with a 25k rotational life expectancy. 785-531C10k for $6.76 Both of these handle 2 watts. It looks like the control switches for my VFD should be momentary switches. You can always test that with a wire that has two bare ends. Just touch two appropriate control contacts, while staying away from R,S,T and U,V,W and other big screw terminals. i RWL |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On 2009-09-01, Ignoramus15363 wrote:
On 2009-09-01, Gunner Asch wrote: On 1 Sep 2009 06:09:17 GMT, "DoN. Nichols" wrote: [ ... ] Typical pot is a 5K or 10K linear pot with a 2W power rating. As for the switch -- make it a SPDTCO (Single Pole Single Throws Did you mean double throw? Yes, I did. Got a source for those? For the usual ones -- try Mouser, Digi-Key, and the other electronic suppliers. For the locking handle ones -- those I stumble across at hamfests -- occasionally. O.K. Mouser Electronics has them -- but not cheap. Look at: http://www.mouser.com/ProductDetail/Honeywell/2TL1-1A/?qs=sGAEpiMZZMtygI3JAGOxU%2f5ZR3DSiS2Q assuming that still reaches it. If not. look for Mouser part number 785-2TL1-1A (A Honeywell switch -- about $40.00 in unit quantities. The one shown has to have the handle pulled to switch from any position to any position. There are some which will switch to one side only without pulling, and the other side requires pulling. Others can be switched from either "ON" position to the center "OFF" position, but must be pulled to switch to either "ON". You deal with enough surplus stuff so once you know what they look like, you can keep your eyes open for them. They are normally used for things like activating munitions in an aircraft, where you don't want someone to accidentally switch something explosive on. :-) On eBay -- these look like possibilities: 300333989154 This one is lacking the center off, but it has a close-up which shows how the locking works. 330259446730 But if you have to *buy* switches *new*, look for large pushbuttons, with the locking mushroom switch for the panic stop function. You can get those at places like Grainger, if you have the ability to buy there. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
Was- Arboga mill converted to VFD - now Q about pot & switchesfor VFD
On 2009-09-02, DoN. Nichols wrote:
O.K. Mouser Electronics has them -- but not cheap. Look at: http://www.mouser.com/ProductDetail/Honeywell/2TL1-1A/?qs=sGAEpiMZZMtygI3JAGOxU%2f5ZR3DSiS2Q assuming that still reaches it. If not. look for Mouser part number 785-2TL1-1A (A Honeywell switch -- about $40.00 in unit quantities. The one shown has to have the handle pulled to switch from any position to any position. There are some which will switch to one side only without pulling, and the other side requires pulling. Others can be switched from either "ON" position to the center "OFF" position, but must be pulled to switch to either "ON". You deal with enough surplus stuff so once you know what they look like, you can keep your eyes open for them. They are normally used for things like activating munitions in an aircraft, where you don't want someone to accidentally switch something explosive on. :-) On eBay -- these look like possibilities: 300333989154 This one is lacking the center off, but it has a close-up which shows how the locking works. 330259446730 But if you have to *buy* switches *new*, look for large pushbuttons, with the locking mushroom switch for the panic stop function. You can get those at places like Grainger, if you have the ability to buy there. Don, I thought that you initially discussed a pot/switch combination? i |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
In article ,
Ignoramus15363 wrote: The switch 's resistance should be much less than the input impedance, but big enough so as not to exceed the limit on current produced by the CC terminal. 5k should most likely work and those are very common pots. I put a 1k pot in my drive the other day and it works great. That will be at the lower limit, but should be just fine. VFD makers specify 2 watt pots for mechanical robustness, not electrical load. Nor do you want machine vibration to cause the pot to walk. One thing about the Forward-Off-Reverse switch: Do not make it too easy to operate, or the machine may start when you accidentally brush the switch. The classic scenario is that one is setting things up, and gets chopped up when the machine starts unexpectedly. So use nice big and clunky switches, even though the current is maybe 10 milliamps. Joe Gwinn On 2009-09-01, DoN. Nichols wrote: On 2009-09-01, Gunner Asch wrote: [ ... ] Look in the wiring diagrams and it should show you what value the pot is supposed to be. Generally....0-5k...some are 0-10k, others are different. Yes -- but these are common ratings. This is not something to guess at. If you do..you will never get it going fast enough...or ever get it going, or ever get it going slow enough..... Hmm ... that effect would be more if it were being wired and used as a rheostat instead of a potentiometer. Normally, the VFD has three pins for use with a pot. One is common ground, one puts out 10V or 5V, and the third connects to the wiper. Usually, the output voltage is capable of sufficient current for 1K, 5K or 10K, and what really matters is the voltage which the wiper returns to the control input, which should cover the same range with any reasonable value of potentiometer. Go really too high, and you are likely to pick up noise which will cause the speed to vary a lot at mid range settings. Go really too low, and the 5V or 10V output can't provide enough current, and the voltage will be too low so you can't get enough speed. But anything from 1K to 10K should be fine -- with values beyond that possibly encountering problems. But it is not a critical value. Enjoy, DoN. |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On 2009-09-02, GeoLane at PTD dot NET GeoLane wrote:
I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? RWL Look in the wiring diagrams and it should show you what value the pot is supposed to be. Generally....0-5k...some are 0-10k, others are different. Gunner Thanks Gunner, Iggy, Don I scanned through the manual looking for the wiring diagram and next to the potentiometer it says "10k ?" I"m not sure why the "?" is Are you sure that is not an Omega with part of the printing missing? I can't get my editor/system to create one, but you can use wikipedia to display it: http://en.wikipedia.org/wiki/Omega Anyway -- the upper case Omega symbol is commonly used as shorthand for "Ohms", so that is saying "10 K Ohms". printed in the book but that's what it says. I looked at the on line listing at Radio Shack - not too pricey, about $3. The only problem is, they only list 0.5W potentiometers and Don had mentioned it ought to be 2 Watts. Some of the makers suggest 2 Watt pots. One reason is that there is more resistance element area so it will run longer before it gets noisy. Even at worst case (the DC motor controller which puts 20 V across the pot, and using a 1K pot instead of a 5K pot, we are still really under 1/2 Watt. But -- the larger 2W pots generally have a better feel and greater ease setting a particular value, so I would use them anyway. I looked in the Mouser catalog and I spot two that would probably do the job. One's a high precision single turn pot EUP-1400-10k for $4.15. The other is listed as a 53 series industrial pot with a 25k rotational life expectancy. 785-531C10k for $6.76 Both of these handle 2 watts. O.K. The first one looks nice. 270 degree rotation is normal, but when it said "single turn" and "precision" I was afraid that it had no stops so it would keep going from 0 up to full and then back to zero. These are used for some instrumentation type tasks, but would be poor for controls of this sort. However, what you have found should be a very nice one. The wirewound element will work well for a long time. And they claim 100K rotational life for the first one. I can't seem to find the second one by that part number. It looks like the control switches for my VFD should be momentary switches. That depends. Usually there are usually wiring configurations for momentary pushbuttons (with a NC (Normally Closed) pushbutton for the stop), or for rotary or toggle switches). (Different pages in the manual, usually.) If retrofitting a machine which had a drum switch, I would use the continuous contact wiring pattern, selecting the proper contacts out of the drum switch, so I could continue to use the same control that I was accustomed to. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On 2009-09-02, Ignoramus15363 wrote:
On 2009-09-02, DoN. Nichols wrote: O.K. Mouser Electronics has them -- but not cheap. Look at: http://www.mouser.com/ProductDetail/Honeywell/2TL1-1A/?qs=sGAEpiMZZMtygI3JAGOxU%2f5ZR3DSiS2Q assuming that still reaches it. If not. look for Mouser part number 785-2TL1-1A (A Honeywell switch -- about $40.00 in unit quantities. The one shown has to have the handle pulled to switch from any position to any position. There are some which will switch to one side only without pulling, and the other side requires pulling. Others can be switched from either "ON" position to the center "OFF" position, but must be pulled to switch to either "ON". You deal with enough surplus stuff so once you know what they look like, you can keep your eyes open for them. They are normally used for things like activating munitions in an aircraft, where you don't want someone to accidentally switch something explosive on. :-) [ ... ] Don, I thought that you initially discussed a pot/switch combination? No -- that was someone else. The combination would limit the ability to get really slow running for positioning a chuck or something similar. (You don't want to run the motor for any significant time at that low a speed unless you have made provisions for an external fan to force air through the motor.) Also -- the switch in the pot knob is a bit harder to shut off in a hurry. The red mushroom panic switch is best, next is the usual drum switch wired to control the VFD. I actually have a switch which I intend to use when I put three phase on my Clausing. It is a lever in a pleated rubber boot which rotates a shaft with cams operating three switches -- one at the zero center position, and one switch for each direction of travel. But the cam also has a 1/4" hex socket which can accept the shaft of a potentiometer and which rotates through the standard 270 degrees. So what I want is a 10K pot with a center tap so I can wire it for half on each side of the center off position, using the cam switches to select the direction, and the half of the pot operated by the lever to select the speed. (The assembly came from a hamfest, and I have no idea where to get more of them, but I knew what I wanted it for as soon as I saw it. :-) Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On Mon, 31 Aug 2009 21:48:17 -0400, GeoLane at PTD dot NET
GeoLane at PTD dot NET wrote: In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? Something I could pick up at Radio Shack or do I need to order on line? Under what section of the manual would you go looking for specs if it's something that varies by manufacturer and model? I only read enough of the manual to get my mill up and running so I could play with it. Now that I've had it for several months, it's time to make improvements. RWL VFDs supply the speed pot from a low impedance DC source typically 10V or less and the pot slider is almost completely unloaded. This makes the choice of pot value very non critical - any pot resistance between 3 and 10kohm is typically recommended as suitable and an even wider range would make little difference. Power dissipation is also very low. Even in the worst case scenario, with the lowest value pot, dissipation is much less than 1/4W so even small radio type pots are perfectly usable. However you may prefer the mechanical ruggedness of a pot with higher power rating. What is seldom mentioned, but important in practice, is the resistance law. Most wirewound and many film pots are linear law which is not very suitable for a machine tool working over a wide range of work/cutter diameter and speeds. The useful low speed end is limited to narrow region near anticlockwise. What is preferable is is a log law pot as this opens up the low speed end and gives a close approximation to equal % speed change for equal pot angle change over the whole speed range. Log law radio type pots are easy to find but heavy duty types are much less common. A solution that I find preferable is switched speed setting. The 12 step series resistor sequence 100 Ohm 120 150 180 270 330 390 470 560 680 820 Gives a constant 20% speed change per step which is about as close as is ever needed in typical machine tool use For more VFD information try "Electric Motors"- second edition- Jim Cox Pentagrid |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
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Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On 3 Sep 2009 03:33:40 GMT, "DoN. Nichols"
wrote: Thanks Gunner, Iggy, Don I scanned through the manual looking for the wiring diagram and next to the potentiometer it says "10k ?" I"m not sure why the "?" is Are you sure that is not an Omega with part of the printing missing? That was a good thought. I ran upstairs and looked in the printed manual. There it is printed as the ohm sign, so it is 10,000 ohms. When I made my previous post, I had been looking in the manual that I had downloaded as a pdf file and that's where the omega appears as the "?". I tried using copy and paste from the windows character map to paste an ohm symbol into this reply, and it came out as a question mark rather than an omega, so on an electronic file, the omega is being misinterpreted by the computer as a question mark. RWL |
Was- Arboga mill converted to VFD - now Q about pot & switchesfor VFD
GeoLane at PTD dot NET wrote:
On 3 Sep 2009 03:33:40 GMT, "DoN. Nichols" wrote: Thanks Gunner, Iggy, Don I scanned through the manual looking for the wiring diagram and next to the potentiometer it says "10k ?" I"m not sure why the "?" is Are you sure that is not an Omega with part of the printing missing? That was a good thought. I ran upstairs and looked in the printed manual. There it is printed as the ohm sign, so it is 10,000 ohms. When I made my previous post, I had been looking in the manual that I had downloaded as a pdf file and that's where the omega appears as the "?". I tried using copy and paste from the windows character map to paste an ohm symbol into this reply, and it came out as a question mark rather than an omega, so on an electronic file, the omega is being misinterpreted by the computer as a question mark. Does ALT234 (Ω)work? --Winston |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On 2009-09-04, Winston wrote:
GeoLane at PTD dot NET wrote: On 3 Sep 2009 03:33:40 GMT, "DoN. Nichols" wrote: [ ... ] Are you sure that is not an Omega with part of the printing missing? That was a good thought. I ran upstairs and looked in the printed manual. There it is printed as the ohm sign, so it is 10,000 ohms. When I made my previous post, I had been looking in the manual that I had downloaded as a pdf file and that's where the omega appears as the "?". I tried using copy and paste from the windows character map to paste an ohm symbol into this reply, and it came out as a question mark rather than an omega, so on an electronic file, the omega is being misinterpreted by the computer as a question mark. Does ALT234 (?)work? Well ... it shows up as a '?' here, which means that it is using the section of the extended ASCII characterset with represents control characters with the parity bit set instead of clear. Sun refuses to display these -- at least with the ISO-8859-15 characterset which I use. Perhaps it is characterset dependent. And assuming that the 234 in ALT234 is an octal number, it does land in the parity-bit-set control character range (0x9c, with 0x80 through 0x9f being the extended control characters. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
Was- Arboga mill converted to VFD - now Q about pot & switchesfor VFD
DoN. Nichols wrote:
On 2009-09-04, Winston wrote: GeoLane at PTD dot NET wrote: On 3 Sep 2009 03:33:40 GMT, "DoN. Nichols" wrote: [ ... ] Are you sure that is not an Omega with part of the printing missing? That was a good thought. I ran upstairs and looked in the printed manual. There it is printed as the ohm sign, so it is 10,000 ohms. When I made my previous post, I had been looking in the manual that I had downloaded as a pdf file and that's where the omega appears as the "?". I tried using copy and paste from the windows character map to paste an ohm symbol into this reply, and it came out as a question mark rather than an omega, so on an electronic file, the omega is being misinterpreted by the computer as a question mark. Does ALT234 (?)work? Well ... it shows up as a '?' here, which means that it is using the section of the extended ASCII characterset with represents control characters with the parity bit set instead of clear. Sun refuses to display these -- at least with the ISO-8859-15 characterset which I use. Perhaps it is characterset dependent. And assuming that the 234 in ALT234 is an octal number, it does land in the parity-bit-set control character range (0x9c, with 0x80 through 0x9f being the extended control characters. Yes, that was Unicode UTF-8. Just checking. Thanks DoN. --Winston |
Was- Arboga mill converted to VFD - now Q about pot & switches forVFD
GeoLane at PTD dot NET wrote: In addition to the old gearbox speed changer, speed can also be varied with a pot (0-60 Hz). I have a TECO FM-50 for a 2HP Bridgeport. A pot and on-off switches in a separate box would be a lot more convenient. What are typical specs for a potentiometer for one of these? Something I could pick up at Radio Shack or do I need to order on line? Under what section of the manual would you go looking for specs if it's something that varies by manufacturer and model? I only read enough of the manual to get my mill up and running so I could play with it. Now that I've had it for several months, it's time to make improvements. RWL Radio Shack pots are garbage. Spend a few bucks and buy something like this: http://www.potentiometers.com/seriesRV4.cfm? then it will last for years. I might even have one laying around that would work. They are mil spec, and availible surplus. They are sealed, so you don;t have to wory about dust or metal chips damaging them. -- You can't have a sense of humor, if you have no sense! |
Was- Arboga mill converted to VFD - now Q about pot & switchesforVFD
Ignoramus15363 wrote: If the control voltage is 10 volts, then a 10k potentiometer would dissipate 10v*10v/10000ohm = 0.01 watts. You do not need a 2 watt 10k pot. The two watt pots are made for long life, and have lower wiper noise that the cheap crap. They were used as volume controls in military radios and other electronic equipment in WW-II, and are still good. Buy cheap crap if you want to, but cheap pots are a foolish investment. -- You can't have a sense of humor, if you have no sense! |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
On 2009-09-07, Michael A. Terrell wrote:
[ ... ] Radio Shack pots are garbage. Spend a few bucks and buy something like this: http://www.potentiometers.com/seriesRV4.cfm? then it will last for years. Yes -- so that is who took over the Allen Bradley line of mil-spec pots. Glad to know that quality pots are still made. Enjoy, DoN. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
Was- Arboga mill converted to VFD - now Q about pot & switches forVFD
"DoN. Nichols" wrote: On 2009-09-07, Michael A. Terrell wrote: [ ... ] Radio Shack pots are garbage. Spend a few bucks and buy something like this: http://www.potentiometers.com/seriesRV4.cfm? then it will last for years. Yes -- so that is who took over the Allen Bradley line of mil-spec pots. Glad to know that quality pots are still made. Buy good pots once, or crap every six months. I prefer quality over quantity. :) They are the only used pots worth salvaging from scrap industrial and Military electronics. -- You can't have a sense of humor, if you have no sense! |
Was- Arboga mill converted to VFD - now Q about pot & switches for VFD
In article ,
"Michael A. Terrell" wrote: Buy good pots once, or crap every six months. I prefer quality over quantity. :) They are the only used pots worth salvaging from scrap industrial and Military electronics. I'm looking for a source of 5K pots that cover their whole range within 45 degrees of deflection either way from center. i.e. Set so each end to the wiper is 2.5K and moving the wiper 45 degrees either way will bring that side to zero. I didn't see anything like that on the URL cited. Anybody have any ideas where I could buy small quantities? Meanwhile, still Googling. |
Was- Arboga mill converted to VFD - now Q about pot & switches forVFD
John Husvar wrote: In article , "Michael A. Terrell" wrote: Buy good pots once, or crap every six months. I prefer quality over quantity. :) They are the only used pots worth salvaging from scrap industrial and Military electronics. I'm looking for a source of 5K pots that cover their whole range within 45 degrees of deflection either way from center. i.e. Set so each end to the wiper is 2.5K and moving the wiper 45 degrees either way will bring that side to zero. I didn't see anything like that on the URL cited. Anybody have any ideas where I could buy small quantities? Meanwhile, still Googling. A standard pot is 270 degrees You could use a three to one gear drive. -- You can't have a sense of humor, if you have no sense! |
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