Hey I got a costumer that had us replace a vfd, I guess he had some shitty weird brand vfd and it was working for years until one day it just stopped. So he bypassed it until he ended up buying a used powerflex 523 and I set it up and wired it up and it never gets up to 60hz. It gets up to...

Hello I have a powerflex 400 of 25HP for a 60amp 25HP motor, the motor have a belt that move the clarifier of milk. It is a process that requires strength to move. So I try with the motor without the clarifier the vdf works well with a constant amp of 12 to the max of 50hz that is set up with a...

Is a disconnect required for an auto lift and where does it have to be located? I have a customer that owns an auto garage and he wants me to wire a car lift for him but I haven't really done this type of work before. (I usually do residential and, sometimes, I do light commercial.) The main...

I have worked with people on installing and setting up VFDs, and I have had multiple people say "never run a VFD without a load connected to it or you will fry it". I had no reason to doubt them so that's what I went with, until now. I tried googling it to see why exactly it is bad, but I...

I’Hi all, This is my first post so please bear with me. I'm working on a biogas powered generator that consists of an asynchronous 55kw 3ph 400v motor coupled to a v8 gas engine that supplies powder to the grid. It has been in use for just over two years. To start, the engine starter is...

Assuming that I'm considering motor power factor, efficiency, altitude correction and all those fancy but critical factors... which current should I consider as input to cable sizing by voltage regulation: 600V or 575V? FLA is defined as the current at full capacity drawn by the motor at rated...

I would post the smell here if i could. ha ha ha! One of the shop workers somehow jammed a 208V plug into a 600V outlet. Then somehow was able to rotate it and turn on the contactor! :surprise: we've had a meeting since then with the workers and plug safety - and if it doesn't fit, don't...

Hi all, I am looking for a way to calculate faults relative to motors existing in the system. Is there any way for doing this in a simple way? An example is When we have a 400hp motor on the left side (600V) of a 300kVA transformer, and a 100hp on the right side (208V) of the transformer. I want...

I am doing some calculations for RLA and FLA (I don't have to use direct current amps on the motor plate or from NEC table). I was surfing this page: http://c03.apogee.net/contentplayer/?coursetype=md&utilityid=elpaso&id=12592 where it says On another page the electrical formula says: Link of...

I put in a circuit for a couple of sump pumps today. The nameplate rating on each of the sump pumps was approx. 9.5 amps. (I know it was 9.something.) I put both on a single 20A circuit. I am probably overthinking this, but I am wondering what the chance is of both of them starting at the same...

Hi everyone. I've got a question from an employer. Please give me some explaination. Thanks in advance. A motor 50kw controlled by v/f method. now F=50hz. If f=40hz. P=?

Hi there, I am running a wire from my 1HP VFD to my 1/2 HP motor. I have decided to just run 12/3 BX instead of the braided cable because there are no other sensitive loads around. It's a short run. 10ft so I am not worried about noise. But my question is, the peckerhead on the motor has a KO...

I've got a practical bench test coming up and I know I'll have to megger a DC motor which (I have heard from prior test takers) has 9 unidentified leads coming out of it. No big deal but I was wondering if anyone had practical advice on differentiating the interpole leads from the series and...

Hi all, I am currently trying to size my circuit conductors and breaker for a paint booth. The electrical in the booth consists of: - 20 LED lights @ .45amps each..... 9amps - 1 10hp 208volt motor....... NEC FLC 30.8amps - 1 7.5hp 208volt motor...... NEC FLC 24.2amps Now, what I have found...

Hi all, I am currently trying to size my circuit conductors and breaker for a paint booth. The electrical in the booth consists of: - 20 LED lights @ .45amps each..... 9amps - 1 10hp 208volt motor....... NEC FLC 30.8amps - 1 7.5hp 208volt motor...... NEC FLC 24.2amps Now, what I have found...

What are the limitations for using a motor rated switch as a disconnect. For example: if I had a 20hp, 460v, 3 phase motor (which has a 27 amp FLC), and proper motor overloads. Could I use a 30A motor rated switch as long as it's rated for 20hp and I have the proper circuit breaker at the...

Hi all: I just received two Yaskawa P1000 configured VFDs, with input rating of 460V, 207A, 3ph. The drives came with 400A disconnects and 500A fuses installed. My question is this, if the NEC requires conductors to be sized not less than 125% of rated input current, why does this have...

I am currently building a motor starter for an industrial fan application. The fan is 480V, but the voltage is stepped down to 120V for the control circuit. The on/off button assembly is mounted to the door of the enclosure (120V supply). The enclosure that I bought (Wiegmann) is quite small...

I'm a mechanical engineer, so this is a little out of my expertise. I have a main distribution that's rated at 480 VAC, 225 A running through a wye transformer rated at 480 VAC - 480/277 VAC to a sub panel rated at the same 480/277 VAC. I'm trying to operate a motor at 460 VAC, 38.1 FLA...