Spindle Motor on PM-30MV Integration into Acorn

All things related to the Centroid Acorn CNC Controller

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suntravel
Posts: 1967
Joined: Thu Sep 23, 2021 3:49 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 6433DB0446C1-08115074
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
Location: Germany

Re: Spindle Motor on PM-30MV Integration into Acorn

Post by suntravel »

Yes, I have a 2.2kw Delta EL VFD on my beltgrinder, it limits output amps, but if you can not bring 18.5 A to the Baldor, torque will be less also...

My JMC servo with driver and wiring for 559€ and build in resistor can go with 0.2 s acceleration and deceleration time. Thats way faster the Delta can do, but no resistor here, maybe I add one.

For me the JMC sounds still as the best drive to have high power with small weight for a dynamic moving Z-axis...

... maybe a Kollmorgen Servo with higher speed rating, but also very expensive.

Uwe
firebrick43
Posts: 21
Joined: Sat Jan 08, 2022 10:16 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: none
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No

Re: Spindle Motor on PM-30MV Integration into Acorn

Post by firebrick43 »

They don't actually have less torque because of less amps. VFD don't actually produce true ac wave forms. They take DC voltage(so do servo drives) and modulate the pulses in the mhz range very quickly and at the same time modulate the voltage in amplitude to form a representation of the AC wave form.

These pulses at low rpm can actually be 1000v. This is the big reason inverter rated motors have H class insulation. Regular 3 phase motors with lower class insulation tend to have hole blown in it if they are run below 20 hz for significant time. But the quick high voltage pulses can produce good toque without the huge amps that a motor hooked straight to the mains experiences when trying to start a load from a full stop.
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