I had a question from a fellow member about sizing his supply circuit to match his potential upgrade from router to air cooled spindle. Here are his specs below. Based on his specified VFD with the potential for 35 amp current draw, and adding in a 25% safety factor, I recommend a 40 amp breaker with #8 wire size from his 220/240 Vac supply to his VFD. Typical 10 hp motors draw around 30 amps at full load. I'm not sure if this applies to 3 phase spindle motors. The specs for the spindle show 15 amp current draw.
He responded that he intends to run this new spindle from a 20 amp circuit using #12 wire. What are your thoughts? I would be particularly interested to hear what Gary has to say about this.
Thanks,
David
VFD 7.5KW,Variable Frequency Drive 35A,CNC VFD Motor Drive Inverter Converter 220V,for Spindle Motor Speed Control (1or 3 Phase Input, 3 Phase Output)
I am hoping this is the correct unit for the spindle below , the 380 v is a concern to me as no output voltage is mentioned
Specification
Rated power
7.5 KW
Voltage
380 V
Current
15.0 A
Frequency
300 Hz
Collet
ER32 (6 mm)
Rotating speed
1-18000 rpm
Runout off
0.01 mm
Connection of spindle end
ER32 Φ4-Φ20
Bearing model
6005 x 1,7008 x 2
Torque
3.98Nm