June 3, 20233 yr I have a 5.5Kw 3 phase stepper motor driven by a 1410rpm 230V 550W motor at 3000rpm (4750 rpm). 3-phase rectifier bridge + 15,000uF capacitor. This is how you get 240VDC 3000rpm or 330VDC 4750rpm. If I were to connect this to a 5600W solar inverter (e.g. Axpert VM4) (120V-450V). Would it work?
June 3, 20233 yr 5 minutes ago, usr023 said: I have a 5.5Kw 3 phase stepper motor driven by a 1410rpm 230V 550W motor at 3000rpm (4750 rpm). 3-phase rectifier bridge + 15,000uF capacitor. This is how you get 240VDC 3000rpm or 330VDC 4750rpm. If I were to connect this to a 5600W solar inverter (e.g. Axpert VM4) (120V-450V). Would it work? As an explorer I would at least try it as long as you accept the risk. I would start with a 10ohm series resistor of about 500W or more. Also have no load on the inverter and batteries at least at 85% SOC and measure voltage and current at the same time.
June 3, 20233 yr 11 minutes ago, usr023 said: I have a 5.5Kw 3 phase stepper motor driven by a 1410rpm 230V 550W motor at 3000rpm (4750 rpm). I'm confused! How do you drive a motor by another motor with different rpm? Don't understand.
June 3, 20233 yr 13 minutes ago, Beat said: I'm confused! How do you drive a motor by another motor with different rpm? Don't understand. Different pulley sizes if belt driven?
June 3, 20233 yr Author Motor: 1410rpm, 550W, 230V 3100rpm-240VDC driven pulley size is: 80mm drive pully size is: 180mm 4750rpm-340VDC driven pulley size is: 80mm drive pully size is: 270mm PM generator/servo motor: 5.5Kw, 3phase I don't want to ruin the inverter, so I have to figure out how to do it first. If at all possible. Edited June 3, 20233 yr by usr023
June 3, 20233 yr I can understand why you want to run an "alternator" from mechanical input power such as a diesel or petrol engine, a water wheel, or something similar, but why run from a 230VAC motor? Why not use the 230VAC as is? Is this only a test setup to later replace the AC motor with an ICE-engine? The only potential problem I see is that single phase rectification would produce a fair amount of ripple, even with a 15000uF cap. 3-phase alternator would produce much less ripple. A solar panel can be modelled as an ideal voltage source with a series output impedance. For instance, a particular Canadian Solar 360W panel might have Vmp=39.6V, Imp=9.10A and Voc=47.0V Thus, output impedance Zo = delta_V / delta_I = (47.0-39.6) / 9.1 = 0.81 ohms If you where to connect X panels in series, you would obviously increase the Zo by a factor X. Modelling your 3-phase alternator/ bridge rectified and smoothing cap would be a bit more difficult. As a 1st order estimate you could assume that it is only the capacitor's ESR which you could look up on a datasheet of that specific capacitor you use. There are a few different MPPT algorithms used and I really don't know much about these. I would hope and presume that AC ripple on the input is too high a frequency for the MPPT to react on, otherwise the MPT could become unstable with weird side-effects. I would be a bit concerned of overloading your 550W drive motor. A MPPT is supposed to adjust to your input power source, but this depends on the correct source impedance. With a real solar panel, that is a given, but in your setup, the smoothing cap changes the source impedance. If you make the series resistor too small, you will overload the motor. If you make the resistor too big, you will loose a lot of power as heat dissipation and limit the already lowish 550W power source. @Scorp007 suggestion of starting with a 10 ohm resistor sounds about right. Best would be to use a wire-wound rheostat with a sliding contact that is adjustable. Monitor the input power to your motor and then slowly reduce the resistor until your motor runs at close to maximum power. As you only have 550W peak input power, your MPPT should be able to handle it without problems. BTW, a 15000uF 400V or higher capacitor... I think will require a wheelbarrow to cart around. Not to mention your servo motor. If you sell that heavy machinery you should get enough money to buy a 230VAC high power battery charger.. 😆
June 4, 20233 yr 17 hours ago, usr023 said: Motor: 1410rpm, 550W, 230V 3100rpm-240VDC driven pulley size is: 80mm drive pully size is: 180mm 4750rpm-340VDC driven pulley size is: 80mm drive pully size is: 270mm PM generator/servo motor: 5.5Kw, 3phase I don't want to ruin the inverter, so I have to figure out how to do it first. If at all possible. Just supply more information about how you want to drive the 5.5kw servo motor in order to get the DC power. @Modina I think the size of the cap bank is not close to your size. In a single layer you would only need 288x360x35mm space if made up of 3300uF 50V connected 8 in series and 40 in parallel. A greater concern is that these will cost R3000-R6000. The cheapest way to create the 10 ohm resistor would be 4x12Vx55W car headlight bulbs using single filament in series or 2x2 filament 12V 55W bulbs. This will allow 5A to flow before the bulbs will blow. Bulbs would also provide a visual indication of current flowing. Edited June 4, 20233 yr by Scorp007
June 4, 20233 yr Author There is only one phase. But I can also use a 3-phase drive motor with a VFD. I will also try the flywheel. I don't want free electricity, as you can see in many youtube videos, which I don't think works. The goal would be to produce the highest possible power with the lowest possible energy (500W-1KW max.)I think there is a chance for that. Anyway, there is another servo motor of the same type, which is 12KW.
June 4, 20233 yr 19 hours ago, usr023 said: Motor: 1410rpm, 550W, 230V 3100rpm-240VDC driven pulley size is: 80mm drive pully size is: 180mm 4750rpm-340VDC driven pulley size is: 80mm drive pully size is: 270mm PM generator/servo motor: 5.5Kw, 3phase There are always ways to do simple things a complicated awkward way if you are looking for problems and troubles. Why not get a simple 230V battery charger?
June 4, 20233 yr 7 hours ago, usr023 said: The goal would be to produce the highest possible power with the lowest possible energy (500W-1KW max.)I think there is a chance for that. With each convertion you loose power due to losses. Weather it is electrical or mechanical. There is no way to create energy or destroy it but you can convert it. Simple laws of physics. So an input of 1kW say from 220V AC can at times yield as little as 0.6kW after losses through the drive train and converting to what you need. Even a simple fan belt drive looses quite a bit in power. Edited June 4, 20233 yr by Scorp007
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