And what is wrong with these, once upon a time our Tv's used to have two, one for 405 VHF and the other 625 UHF for changing between the three B&W channels available, and they were very clunky with big bakelite knobs .
three phase motors
- Thread starter clive griffiths
- Start date
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Nothing atall, until they become so worn that your selector lever flops an inch or more from side to side in each position, and bounces around while the machine is running. So I have made my own rotary switch, using the original lever and knob, which now locks nice and solidly into each position. This controls forward reverse and stop functions. For the two speed motor control I repurposed the original rotary switch for the coolant pump to have two poisitions, which now command the two pre set frequencies on the vfd.
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That takes me back to my metalworking class at school, they don't make machines like that anymore and I have known several prototyping workshops that used them because they deliver and the guys loved using them. Never had the big off button, wall isolator and a lever to start.
I don't like the off button either, still looking to fit something more in keeping with the machine, but it was one I had lying around to get it going. Fortunately it fits to a removable plate so no modifications to the machine to fit it. I have since managed to find an original plate with the simple green and red on off buttons as originally fitted, but they are just spring loaded buttons, I don't have the switches they originally operated. Just need to get round to fitting up some suitable switch gear to work with them. One more job on the to do list!
The vfds are mounted on an aluminium plate at the back of the machine. The plate sits on rubber cotton reel anti vibration mounts. The three fused supply boxes are for the two vfds, and the worklight. The coolant pump operates from the smaller vfd via a paddle on off switch and pot to control the speed. These are mounted in a small metal project box attached to the splashback.
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Hmmm. DIY job then...
1. Please don't tell me that I can see brown, blue and yellow conductors without secondary insulation below the left hand VFD.... that was lazy, I rather think that you know that's an immediate fail but it's a consequence of:
2. What's the IP rating on those VFDs if the next owner were to run flood coolant on the machine ? In a workshop, they should be in a box.
It does look like you've used decent rubber flex for your cabling though. Points for that
My old 1949 L5 came with a 4kW 3ph motor replacement and a VFD. It took me a couple of hours to strip both and hoover the brass out of the insides because his electrical mate hadn't put the 1.5kW VFD in a box. He had also installed the motor with the cable entry into the top not bottom of the motor terminal box and had done some nightmare conduit job with plumbers fittings. It left an open end and he just loved cutting brass which gets everywhere ....
The rotor was scratched from all the brass swarf the motor had ingested.
The Yasakawa / Omron drive was actually a real quality piece of kit and cleaned up great but like yours it was meant to be installed in an enclosure.
Both were sold and the electrics replaced in their entirety
A tip for next time : Rather than using a 2 pole 2800 rpm motor which has less low speed torque, fit a 4 pole motor. This gives you higher torque at low speed and set your VFD up for a modest overspeed (say 70Hz) so that you can spin it up to 1.4 x 1440 = 2016 rpm. You get constant power but reduced torque above 50Hz (1440 rpm) but it doesn't matter there as you will be only be using max rpm to spin slender items fast for clean finishing cuts where the torque isn't so essential. As 4 pole and 2 pole motors are mechanically the same, a 4 pole motor will have no issue spinning up to 2800 rpm just like it's 2 pole sibling.
Some people hate motor swaps. I think there is far more room for dangerous errors adding a VFD without the proper knowledge or the attention to detail to do it right in order to protect the next owner of the machine.
1. Please don't tell me that I can see brown, blue and yellow conductors without secondary insulation below the left hand VFD.... that was lazy, I rather think that you know that's an immediate fail but it's a consequence of:
2. What's the IP rating on those VFDs if the next owner were to run flood coolant on the machine ? In a workshop, they should be in a box.
It does look like you've used decent rubber flex for your cabling though. Points for that
My old 1949 L5 came with a 4kW 3ph motor replacement and a VFD. It took me a couple of hours to strip both and hoover the brass out of the insides because his electrical mate hadn't put the 1.5kW VFD in a box. He had also installed the motor with the cable entry into the top not bottom of the motor terminal box and had done some nightmare conduit job with plumbers fittings. It left an open end and he just loved cutting brass which gets everywhere ....
The rotor was scratched from all the brass swarf the motor had ingested.
The Yasakawa / Omron drive was actually a real quality piece of kit and cleaned up great but like yours it was meant to be installed in an enclosure.
Both were sold and the electrics replaced in their entirety
A tip for next time : Rather than using a 2 pole 2800 rpm motor which has less low speed torque, fit a 4 pole motor. This gives you higher torque at low speed and set your VFD up for a modest overspeed (say 70Hz) so that you can spin it up to 1.4 x 1440 = 2016 rpm. You get constant power but reduced torque above 50Hz (1440 rpm) but it doesn't matter there as you will be only be using max rpm to spin slender items fast for clean finishing cuts where the torque isn't so essential. As 4 pole and 2 pole motors are mechanically the same, a 4 pole motor will have no issue spinning up to 2800 rpm just like it's 2 pole sibling.
Some people hate motor swaps. I think there is far more room for dangerous errors adding a VFD without the proper knowledge or the attention to detail to do it right in order to protect the next owner of the machine.
Bob Chapman
Established Member
Fergie 307 - You mention that the jog facility is very useful. I have this on my wood turning lathe but don’t know what to use it for. Would you mind explaining how it is useful?
Bob
Bob
Sideways, your are a sharp eyed man. Yes you do see cables without secondary insulation. The photos were taken at the stage where it was roughly set up to check everything worked. The cable was cut to the wrong length, and has since been changed. As for UP rating, flood coolant it's not something I use. I don't use water based coolant full stop, and the motor isn't set up to provide that level of flow. In addition to the chip tray and splash back There is an additional plate fitted under the tray and sticking out above the whole lot, with the machine in position this buts up to the wall. There is no way for coolant to come into contact with the electrics directly, and it doesn't produce mist, so not an issue IMHO. Equally there is no way for chips and swarf to get to it either. I have never actually had to clean any coolant or swarf off the shelf at the back, in practice the tray and splash back prevent this. The motor also has an additional shield covering the rear to prevent anything being drawn into it, a lesson learned from my old myford which has the motor completely exposed. As for the motor I am more than happy with it, and given the gearing of the machine the torque really isn't an issue. Interesting to note that of course Harrison themselves saw no reason for additional protection of the motor, and although I have installed an additional shield as a precaution, I have yet to see any evidence of swarf getting anywhere near it. So the machine is entirely safe for the use to which I intend to put it. I see no reason why I would want to take additional measures to protect it from a type of use that I won't be putting it to.
If I were to sell it and the new owner wanted to use full flood cooling I would suggest that it is their responsibility to ensure that it is suitable for that use, perhaps at the same time as they modified it to enable it to do that. I had considered fitting the whole lot inside the cabinet, but this fell short of their recommendations to ensure proper air circulation, so I would have had to cut ventilation holes in the cabinet, not something I would want to do.
If I were to sell it and the new owner wanted to use full flood cooling I would suggest that it is their responsibility to ensure that it is suitable for that use, perhaps at the same time as they modified it to enable it to do that. I had considered fitting the whole lot inside the cabinet, but this fell short of their recommendations to ensure proper air circulation, so I would have had to cut ventilation holes in the cabinet, not something I would want to do.
I can't really think why it would be on a woodworking machine. On a metal lathe it is handy for moving it very small amounts, so for cutting a keyway wider than the broach for example. Just easier/lazier than doing it manually.Fergie 307 - You mention that the jog facility is very useful. I have this on my wood turning lathe but don’t know what to use it for. Would you mind explaining how it is useful?
Bob
IP rating obviously, don't you hate auto correct?
On the subject of enclosures, both vfd manufactures state in the installation instructions that they should be fitted in a suitable enclosure if the environment is dusty or there is any possibility of water ingress. I am fortunate to have a large tool room where these machines live, which only contains metal working machinery, and is neither damp nor dusty. All my wood working machines are in another part of the workshop where they can produce sawdust and chips to their hearts content. So is there any requirement for them to be fitted in an enclosure in any and all circumstances? The manufacturer says not, and none of mine are, don't know if there are electrical regs that say otherwise?
Bob Chapman
Established Member
Thanks Fergie. It sounds like a redundant feature of the vfd which is a later addition to the lathe.
Bob
Bob
Fergie all good, sold !
IP requirements are just about suitability for the application. In your situation, I'm persuaded (not that my opinion matters to anyone and I'm not aware of any generic requirement beyond IP4x on top and IP2x everywhere else which your drives will meet from the look of them.
In another shop, for another user, that installation might not be OK.
The motor story isn't that you need to protect the motor, which is probably a totally enclosed type, just that it's amazing how swarf, grinding dust, wood dust, coolant can find it's way into things unless all the holes are sealed tight with compression glands rather than using brass or plastic grommets.
all good, sold !IP requirements are just about suitability for the application. In your situation, I'm persuaded (not that my opinion matters to anyone
and I'm not aware of any generic requirement beyond IP4x on top and IP2x everywhere else which your drives will meet from the look of them.In another shop, for another user, that installation might not be OK.
The motor story isn't that you need to protect the motor, which is probably a totally enclosed type, just that it's amazing how swarf, grinding dust, wood dust, coolant can find it's way into things unless all the holes are sealed tight with compression glands rather than using brass or plastic grommets.
I couldn't agree more. When I got the Myford there was swarf all over the outside of the motor, and as it turned out quite a bit inside as well! How anyone could think that was safe is beyond me. At the very least you would think it would occur to someone that this would be likely to damage the motor. A very simple curved aluminium guard fitted to the mounting plate was all that was required to prevent this. And proper glands, definitely. A real pet hate of mine is the insulated crimp terminals. Don't get me wrong I can certainly see the attraction in terms of convenience and speed, I just think they look awful.
As you say in other circumstances my set up might not be suitable. I helped a mate out with an installation on an old table saw. He was going to fit the vfd in the bottom of the cabinet, primarily for neatness I think. A look at the dust and general crud that had collected in there, and I was able to convince him that it really wasn't a good idea, unless he wanted to turn it into a barbecue. Ended up fitting it in a box on the wall next to the machine, and with a vent inside the box so it was drawing air for ventilation from the "clean" room on the other side of the wall, rather than the dusty work area.
And of course your opinions matter, that's the beauty of the forum so we can all benefit from others experiences and knowledge.
As you say in other circumstances my set up might not be suitable. I helped a mate out with an installation on an old table saw. He was going to fit the vfd in the bottom of the cabinet, primarily for neatness I think. A look at the dust and general crud that had collected in there, and I was able to convince him that it really wasn't a good idea, unless he wanted to turn it into a barbecue. Ended up fitting it in a box on the wall next to the machine, and with a vent inside the box so it was drawing air for ventilation from the "clean" room on the other side of the wall, rather than the dusty work area.
And of course your opinions matter, that's the beauty of the forum so we can all benefit from others experiences and knowledge.
clive griffiths
Established Member
Well here is an update to the start of this thread and thanks to all for your help, yes it is a Mercury and I would have liked to keep the original motor but local electrical motor companys dont seem interested in small jobs, so it looks like I will go down the single phase road with either a half horse or three quarter hp.
Clive.
Clive.
