- Thread starter optima21
- Start date
time for another update, I've changed the motor to a 3 phase one and fitted a variable frequency drive, as the slowest speed of 365rpm is a bit fast for some boring work and ends up causing the finish on some parts to be pretty rough due to vibration and chatter.
the motor I got was a 3phase 0.25kw 2 pole b34 face and foot mount 63 frame size motor
https://inverterdrive.com/group/Motors-AC/ac-Motor-250-Watts-2-pole-Foot-Face-Mounting/
and a generic cheap 0.75kw variable frequency drive off ebay
https://www.ebay.co.uk/itm/254033253914
the motor will just bolt in place of the old one, but its not that simple as the orginal motor spindle is 14mm dia x 30mm long with a 5mm keyway and the new motor has a 11mm dia spindle x 23mm long with a 4mm keyway. this meant making a new motor coupling,
so here is the original one, about 26mm dia, with a 14mm bore and keyway one end and 10mm bore and keyway at the other end, and is steel.
and this sides onto this shaft in the gearbox, and there is a screw and washer at the end of the shaft, to stop you removing it.
the new coupling was made from aluminium and this is cutting a keyway in the lathe, each cut was 0.025mm deep so it took a while. a hole was drilled in the side as the end of the keyway was blind.
and the new coupling next to the old one
the original one is 45mm long, the one I made is 55mm long and with hindisght I should have made it 62mm long with the keyways being 23mm deep at each end. the extra length means that it doesnt need to be help in place on the gearbox shaft, and a couple of small spacers meant I didnt need to make the new coupling
the motor was then screwed to the mounting plate which was then mounted to the milling head, one of the motors mounting feet was used and had a 1.2mm thick plate bolted to it and the VFD was also screwed to that plate
I kept the original stop and start buttons on the milling machine as they are a nvr switch, just in case there is a powercut etc. One thing that suprised me is how current is being drawn. at 50hz the slow speed (365rpm) draws 1 amp, but at the fast speed (1600rpm) draws 2.5 amps, so Im thinking that the bearings in the quill are a bit tight and need adjusting, but they've been like that since I got it 25 years ago.
if you have one of these VFD's and you want to connect an external speed controller or switches, this video may be of help, but I dont think I'll need that with mine
one little issue I had with the motor was when it was made the nuts for the electrical connections to convert from start to delta, had been overtorqued so has stripped the threads on the studs.
so with the VFD running at 20hz, the slowest speed should be reduced to about 150rpm......think this is an easier option as I was also thinking of making a backgear to fit between the orignal motor and gearbox on the milling machine.
the motor I got was a 3phase 0.25kw 2 pole b34 face and foot mount 63 frame size motor
https://inverterdrive.com/group/Motors-AC/ac-Motor-250-Watts-2-pole-Foot-Face-Mounting/
and a generic cheap 0.75kw variable frequency drive off ebay
https://www.ebay.co.uk/itm/254033253914
the motor will just bolt in place of the old one, but its not that simple as the orginal motor spindle is 14mm dia x 30mm long with a 5mm keyway and the new motor has a 11mm dia spindle x 23mm long with a 4mm keyway. this meant making a new motor coupling,
so here is the original one, about 26mm dia, with a 14mm bore and keyway one end and 10mm bore and keyway at the other end, and is steel.
and this sides onto this shaft in the gearbox, and there is a screw and washer at the end of the shaft, to stop you removing it.
the new coupling was made from aluminium and this is cutting a keyway in the lathe, each cut was 0.025mm deep so it took a while. a hole was drilled in the side as the end of the keyway was blind.
and the new coupling next to the old one
the original one is 45mm long, the one I made is 55mm long and with hindisght I should have made it 62mm long with the keyways being 23mm deep at each end. the extra length means that it doesnt need to be help in place on the gearbox shaft, and a couple of small spacers meant I didnt need to make the new coupling
the motor was then screwed to the mounting plate which was then mounted to the milling head, one of the motors mounting feet was used and had a 1.2mm thick plate bolted to it and the VFD was also screwed to that plate
I kept the original stop and start buttons on the milling machine as they are a nvr switch, just in case there is a powercut etc. One thing that suprised me is how current is being drawn. at 50hz the slow speed (365rpm) draws 1 amp, but at the fast speed (1600rpm) draws 2.5 amps, so Im thinking that the bearings in the quill are a bit tight and need adjusting, but they've been like that since I got it 25 years ago.
if you have one of these VFD's and you want to connect an external speed controller or switches, this video may be of help, but I dont think I'll need that with mine
one little issue I had with the motor was when it was made the nuts for the electrical connections to convert from start to delta, had been overtorqued so has stripped the threads on the studs.
so with the VFD running at 20hz, the slowest speed should be reduced to about 150rpm......think this is an easier option as I was also thinking of making a backgear to fit between the orignal motor and gearbox on the milling machine.
Nickedemuz
Member
- Messages
- 41
- Location
- Sweden
Nice modifications optima21 
I also have a bfe64 but I think the backlash is pretty bad. I'm considering converting it to ball screws. Is that something that you have done as well?
I also have a bfe64 but I think the backlash is pretty bad. I'm considering converting it to ball screws. Is that something that you have done as well?Nice modifications optima21
I dont find backlash to be a problem as I have a 3 axis digital readout. if I didn't Id be struggling to work out the positions sometimes.
pressbrake1
Forum Supporter
- Messages
- 5,483
- Location
- Essex
The machines I got as a school boy and which I learned on.
Bad that it seems every mill made had a wonky column.
A 2mt spindle is available from a supplier in the Czech Republic
Bad that it seems every mill made had a wonky column.
A 2mt spindle is available from a supplier in the Czech Republic
PeterDRG
New Member
- Messages
- 7
- Location
- Istria, Croatia
The later mills from Essel Engineering did come with MT2 spindles.
