mark davison on here has the same mill!
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hermetic
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The thing is the coils inside the motor need to "fire" in the right order so that the rotating magnetic field progresses smoothly round the stator, it could be that one of the coils is connected in the wrong position, so the motor runs ok when not loaded, but is not developing full power when the load comes on. We can presume that all the reds are all the ones, and all the blacks are all the 2's, because of the way it has been previously connected in star, but the A,B and C which designate the position of the coils around the stator has to be determined by trial and error. Connect the motor as in my post above, and listen to it with the belts off, then reconnect it in the second way I describe and try again. You may be able to hear a slight difference in the note of the motor running unloaded, or you can try with the belts on, but in order to change the connections, I guess you will have to remove the motor again!
sorry I missed that , that as im reading is basically what I tried to write
thats what I did and I was satisfied it was correcctyea its a motor out job, i did experiment when connecting the motor and as I said switched two of the black wires deliberately and my god the motor was most definitely not happy about this, now perhaps there was one more untried option hmm I may have to cry ha ha
I may also note that this saga also caused me to rewire my container as I thought I was suffering voltage drop, but with the vfd struggling im still seeing 238 volts at the vfd input wires:/
mtt.tr
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yes your wiring sounds correct
and as @Hopefuldave says, you should be golden assuming no other issue
poles setting on the vfd is just to show correct rpm
Not convineced about correct sequence of the windings there is only 3 sets of windings, as long as they are wired in delta changing the sequence will only change the motor direction, same as swapping any 2 phases will change the motor direction.
Reversing any one set of windings could cause the issue described by hermetic, like mixing up U1 and U2.
The diagram top left of this picture shows it best.
Reversing any one set of windings could cause the issue described by hermetic, like mixing up U1 and U2.
The diagram top left of this picture shows it best.
Not convineced about correct sequence of the windings there is only 3 sets of windings, as long as they are wired in delta changing the sequence will only change the motor direction, same as swapping any 2 phases will change the motor direction.
Reversing any one set of windings could cause the issue described by hermetic, like mixing up U1 and U2.
The diagram top left of this picture shows it best.
mtt.tr
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- Essex/Suffolk border
Not convineced about correct sequence of the windings there is only 3 sets of windings, as long as they are wired in delta changing the sequence will only change the motor direction, same as swapping any 2 phases will change the motor direction.
Reversing any one set of windings could cause the issue described by hermetic, like mixing up U1 and U2.
The diagram top left of this picture shows it best.
Thats entirely correct
because i had 3 reds and 3 blacks that were all connected for star, when i changed it for delta I had 3 possible connections, is that correct? because each of the reds went to a phase regardless, and I tried 2 out of 3 options for the black wires in delta
mtt.tr
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see I labeled absolutely nothing and you must consider the fact that if i was in fact smart, well then I wouldn't be up to stuff like this in the first place would I ha ha
mtt.tr
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Mark Davison
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As Ryan says, I have one of these. Similar 6 pole 100 frame motor, mine is 2hp. I had to modify the windings to dig our the star point and convert it to delta. The last thing you want to do with one of these machines is remove the motor, its a nightmare job! I'm seriously considering swapping to a 4 pole 90 frame 2hp motor that I have to make it easier to get in and out, I don't need the slow speed high torque of the 6 pole.
I run mine on a cheap £60 Chinese 2.2kw vfd. If I tried to start it in a high gear at 50hz from cold it would probably throw an error. The gearbox oil and oil in the head is ISO 200 gear oil. I start it at say 20hz from cold and run for a couples of mins before winding the speed up. I wouldnt say mine ever struggles, but will some times cause an over current error when cold. After 30 mins running the head gets quite warm (bevel gear i assume).
I run mine on a cheap £60 Chinese 2.2kw vfd. If I tried to start it in a high gear at 50hz from cold it would probably throw an error. The gearbox oil and oil in the head is ISO 200 gear oil. I start it at say 20hz from cold and run for a couples of mins before winding the speed up. I wouldnt say mine ever struggles, but will some times cause an over current error when cold. After 30 mins running the head gets quite warm (bevel gear i assume).
Mark Davison
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I had her cutting some raiway track with a 2'' chinese indexible cutter I have previously run on my true 3 phase horizontal/vertical mill, I had to use the low range and run the motor at 100hz to make any progress at all, power is dismal compared to what the real 3 phase was capable of , im wondering what to do,perhaps im expecting too much from a vfd think i was probably running 360 rpm or something like that and any cuts deeper than 1mm would stall the cutter ! I never managed to even come close to stalling the true 3 phase machine
that motor is truly awful to remove
hermetic
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Actually, it is not entirely correct, swapping any two incoming phases will reverse the motor, swapping over the coil ends will make the motor run badly, with low power, and also noisily. As I explained in my earlier post, we are assuming that all the reds are 1s and all the blacks are 2s, if that assumption is correct then we are feeding the coils at the same end for all three, however we have to know how the motor is wound in order to be sure that we have a progressive rotating magnetic field, and the only way to be certain of this is by experiment, and trial and error till the motor runs smoothly and quietly on load. The problem would be best solved by taking the motor somwhere with normal 3 phase and testing it out, Friendly local motor rewinder perhaps?
