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| How to use 92VAC 200Hz AC-servo as spindle motor with 240VAC/50Hz mains? |
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| PekkaNF:
Bill, I can confirm that. This old inverter I have has pretty basic parameters. It basically lets me fudge VF curve with few parameters and one %current limit from full nominal current of the drive. Found only one PWM switching frequency combo that worked without vibration and over current. In the end I'm at: Maximum-voltage frequency 450 Hz (gives nominal input voltage = 230 VAC out at that "speed") PWM 11,7 khz and maximum frequency 960Hz Voltage boost 10,2% Min speed 40.2 Hz Max speed 200 Hz Max continuous current 80% (is actually 1.6A, same as motor plate) 5s ramps up/down, no DC inject on braking There is some room for adjustment, but got it running fine with these. Still has to check what it is when loaded with real life load. Really quiet when running right, but when parameters are wrong it sounds like fistfull of nuts and bolts on the blender. Funny how fast you can release "ON" switch in the quiet night on tranquil garden, when servo motor starts jumping on the table. So there is hope, but clearly this is not as easy as with normal garden rated AC motor. Pekka |
| BillTodd:
Hi Pekka, I'm glad you've got it running :) I'm not surprised the servo motor is sensitive to the VFD's adjustment, it is after all design to reacted rapidly to the driver. I'm wondering if dropping the input voltage slightly to the minimum (to say ~200vac using a auto-transformer ) would give you a greater range of adjustment? Bill |
| PekkaNF:
it is sensitive. Thank you for couragement. I wonder one parameter. It has current mode and voltage mode. Default is voltage mode and it says you can use current mode but has a reference to technical manual and I don't have it. I have one BIG old British made variable transformer that I could use to check if reduced input voltage would do any good, but it is sort of pointless, because there is no way I'm going to put "huge" (relatively speaking) transformer to othervice compact design. Interesting excercise though, and I might actually try it. I'm still wondering if there would be a VFD somewhere that is designed to give 3phase 100-110VAC 2A out....something like a aviation 400 Hz but front end up to 240VAC. This should be easy to PFC. But probably there is no need for it. I have this "need" to check up current and voltage under load, need to borrow a true rms meter to it. I probably don't need it, but just to feel better. Pekka |
| BillTodd:
--- Quote ---I have this "need" to check up current and voltage under load, need to borrow a true rms meter to it. I probably don't need it, but just to feel better. --- End quote --- If you have an oscilloscope, just check for and excessive spikes that could damage the insulation, then, to check the power, just see how hot it gets . Bill |
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