Drillit
23rd June 2013, 03:42 PM
As a matter of general interest, I mentioned a little time ago, that I would post details of an EVS system
that I had retro fitted to my Durden lathe (Top Turn Series 400). The major reason behind my decision was that the lowest speed
was 350 and the highest 3500, via 4 step pulley belt change. I found that the low speed was too fast for large
pieces, particularly on the outboard. So I approached an electrical engineer friend, who could install an EVS system that he made
from scratch. The upgradeinvolved changing the motor to a3 phase, 240V,1.1 Kw, 4 pole, 1425 rpm motor and adding a 1.5 Kw ac inveter, giving the motor a variable speed capability.
The inverter converts a 1 phase, 240V, 50Hz input supply to a 3 phase, variable voltage, variable freaquency supply to control the new motor, which produces 7.5 Nm of torque.
The pulley step 1 - 24.5 rpm to 350 rpm with a torue multiplier of 4. Step 2 63 to 900 with a TM of 1.6. Step 3 126 to 1800 with a TM of .8 and Step 4 - 245 rpm to 3500 rpm with a TM of .4.
It has a Motor Thermal overload protection, inverter cooling fan and inverter braking resistor protection. The speed control box is fixed to the headstockbyway of magnets. I also had included
(as previously) a foot control that I have found to be excellent. The only slight drawback is that the speed controlbox does not give a read outof the spindle speed. To overcome this, I have taped
some silver paper at the spindle and I can get a speed read out from a digital tachometer, if needs be. I hope that this information is not too technical, because that is not my forte.
I have enclosed some pictures so that, my explanation is better understood. The all up cost with a new motor was $1100.00. I, of course, gave the old motor (which worked fine) to my friend. Drillit.273793273794 Havent bothered with lathe photos but electronics box is fixed on and housed at the tailstock end. Happy to answer any questions, I hope. :B
that I had retro fitted to my Durden lathe (Top Turn Series 400). The major reason behind my decision was that the lowest speed
was 350 and the highest 3500, via 4 step pulley belt change. I found that the low speed was too fast for large
pieces, particularly on the outboard. So I approached an electrical engineer friend, who could install an EVS system that he made
from scratch. The upgradeinvolved changing the motor to a3 phase, 240V,1.1 Kw, 4 pole, 1425 rpm motor and adding a 1.5 Kw ac inveter, giving the motor a variable speed capability.
The inverter converts a 1 phase, 240V, 50Hz input supply to a 3 phase, variable voltage, variable freaquency supply to control the new motor, which produces 7.5 Nm of torque.
The pulley step 1 - 24.5 rpm to 350 rpm with a torue multiplier of 4. Step 2 63 to 900 with a TM of 1.6. Step 3 126 to 1800 with a TM of .8 and Step 4 - 245 rpm to 3500 rpm with a TM of .4.
It has a Motor Thermal overload protection, inverter cooling fan and inverter braking resistor protection. The speed control box is fixed to the headstockbyway of magnets. I also had included
(as previously) a foot control that I have found to be excellent. The only slight drawback is that the speed controlbox does not give a read outof the spindle speed. To overcome this, I have taped
some silver paper at the spindle and I can get a speed read out from a digital tachometer, if needs be. I hope that this information is not too technical, because that is not my forte.
I have enclosed some pictures so that, my explanation is better understood. The all up cost with a new motor was $1100.00. I, of course, gave the old motor (which worked fine) to my friend. Drillit.273793273794 Havent bothered with lathe photos but electronics box is fixed on and housed at the tailstock end. Happy to answer any questions, I hope. :B