Guineafowl's latest activity

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...

I don't know the details of the VFD that you're considering, but: Reducing the output frequency would be (approximately) the torque...

Measure the positive reactance of the motor at operating frequency. Then provide negative reactance to cancel most of that.

VFD manual should be linked in the first post. Yes, I thought lifting the car slower might reduce the loading of the system. Or, running...

As a first attempt, looking at the motor plate (connected in star): $$Z=\frac V I = \frac {400} {11} = 36.4\Omega$$ Find capacitor with...

1. Done - it has automatic screw lubricators which have been cleaned out and topped up. 2. Yes, certainly something to try. I assume 3...

Motor plate, for interest:

This one is a 3ph 400V in and out model. Can’t be changed. Cheap enough for a punt on this problem; if no go, I can use it for something...

Power supply to the 7.5kW rotary is 1ph, 240Vac. Supply voltage drop at full load is within 5%. The rotary outputs (roughly) 415Vac 3ph...

I’ve also seen it written: $$\int fg’ \,dx = fg - \int f’g \,dx$$ Maybe you could preface with ‘f and g are functions of x’ and save...

Thanks, that all makes sense. All I will say for the ##uv## version is, it’s briefer, and for the integral bits, there’s a pleasing...

Parts is really the inverse product rule. Start with the product rule for differentiation: $$\frac{d}{dx}\big (f(x)g(x)\big ) =...

Another thing - I didn’t know you could evaluate the ##uv## part of IBP between the limits, as you have done in the square brackets. I...

I thought the comment about initial terms vanishing was a maths/physics in joke, but there it is made real. Your method is a lot...

Integration by parts is valid for a definite integral. That allows you in this case to simplify the integral to a known standard form...