Guineafowl's latest activity
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GWithout a wider range of experimental capacitors, I would use 20uF in that application. It is a case of balancing the inductive...
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GGuineafowl replied to the thread VFD for powering a car lift.Results: Capacitance (uF):Current U:Current V:Current W: 013.413.18.3 1212.812.68.0 209.410.07.2 359.310.57.0 It looks...
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GGuineafowl replied to the thread VFD for powering a car lift.Ok, well I have 30 uF and 20 uF coming, so that will give me the range 12-50 uF. Checking for motor voltage spikes, I assume my Fluke...
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GYou understand the compensation requirements. I have not checked your calculations because your result is in the ballpark I expect...
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GGuineafowl replied to the thread VFD for powering a car lift.An interesting short article on self-excitation in pf-corrected induction motors: https://nepsi.com/resource/Self-Excitation...
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GMoly oil is also available. I'm not sure if the moly will fit through the felt pads. It might depend on the particle size. BoB
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GGuineafowl replied to the thread VFD for powering a car lift.I’ve had the motor apart for testing the windings and changing the bearings: It’s dual voltage, ie 230V delta or 400V star. Latter...
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GGuineafowl replied to the thread VFD for powering a car lift.As soon as power is cut, the motor stops dead from the friction. Does that allay any fears? I’d guess that, at switch-off, we’ll be...
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GDo not overcompensate the motor inductance with capacitors as, when you turn it off, the two will become a resonant self-excited...
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GGuineafowl replied to the thread VFD for powering a car lift.I’ve ordered three ##450V, 30\mu F## capacitors, having approached the calculation differently and got the same answer: At ##400V, 11A...
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GGuineafowl replied to the thread VFD for powering a car lift.Thanks, I’ll get some EP grease. The only problem is, the lubricator is an oil reservoir, 11, and a tight-fitting felt wick, 9, which...
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GThe heating could be induced by the thread profiles of screws and nuts not perfectly matching, as when new. If that is the case...
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GGuineafowl replied to the thread VFD for powering a car lift.The screw is on the right, and turns the other screw via two 90deg gearboxes and a driveshaft under the lift area. The lift nut is no...
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GGuineafowl replied to the thread VFD for powering a car lift.Ok, so a cosphi of 0.65 gives an angle of 49.5 degrees: $$Z=36.4\Omega <49.5° = 23.6 +j27.7\Omega$$ $$C=\frac 1 {2\pi f 27.7} = 115...
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GI don't know the details of the VFD that you're considering, but: Reducing the output frequency would be (approximately) the torque...
