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Today with both the terminators and dv/dt filters back online, the max voltage observed was 740 volts. This same configuration at a 1000 ft distance had a max voltage of 1200 so moving the drives looks to have helped a good bit. My question is if this motor is rated for NEMA Part 31, its...

Think of those VFD output cables as being very powerful radio transmitter antennae. Your cables are now able to pick up stray RFI/EMI signals, This seems like a strong indication of the issue. The other cables to the aerator motors have good seperation. Is there a way to test for that before...

It isn't. The 190-204 doesn't stand up to that kind of measurements. See my notes in previous post - it was exactly that instrument I tried to use. The 1200 V peaks are more in line with a reflection factor at 1.7 - 1.8. Which is normal if there are no motor reactors, but much too high if you...

Thanks for the responses. I'll try my best to answer any questions. - hp? voltage? The 4 motors are 100 HP, 460V Clarification. There used to be load reactors, and then replaced by dv/dt filters. There are line reactors. Where are you taking these measurements? 190-204 Fluke Portable O Scope...

We have a client 4 Vertical Turbine Pumps powered by the following motors: Emerson, BF66, Type-RUSI, Frame 404TP 460v, 3PH, 1785 RPM, 60HZ Class F Insulation, WP1 Motor Data Sheet Calls for VFD Load Type VT/PWM. The VFDs are Altivar 71s. Which from the model number states it is a Constant...

For example, a 4" overflow pipe in an elevated storage tank. If the tank was being filled at 100 gpm and was going past the height of the overflow pipe, what would the head over that pipe be? I was just emailed some handy graphs on circular weir flow from 1964 by F. Caplan. Wish I knew how to...

How do you calculate the head over a pipe when used as a weir, and at what point does it not fucntion as a weir. Thanks.

A wastewater treatment plant has a tertiary filter that discharges over an 8' weir at elevation 18', it falls 5' to elevation 13' (bottom of filter effluent chamber), goes through a 16" 90 deg bend mounted on the side of the chamber down to an opposite faced 90 then runs 20 feet to a contact...