We have a system that is designed for a 480V wye system, and the customer came back stating that their power source has 1 leg grounded (ie delta). Not having dealt with this in awhile, do I just need to make sure any 3phase devices are rated for running off 480V delta?
Regarding the devices on...
Our sales group is quoting a project where an engineering firm has listed out that the safety circuit be powered from a SIL-certified 24VDC power supply. I've gone through the few different brands we typically use for our power supplies (AB, Carlo Gavazzi, Sola) and have found the units have...
I have a 4-20mA transmitter that I need to power up just for using the display on the unit, there's no PLC in the application. I thought 250ohms was the minimum resistance i'd have to wire between the 24VDC supply and the transmitter to simulate the load of the PLC, but wanted to confirm if my...
I was having a discussion recently and wanted to see if I could get some clarification/opinion on a suggestion I received recently.
We have an issue with a 3phase electric heater that is wired in the head and the lack of space has caused the leads to break off and touch the housing sometimes...
We have a control panel in which we'll have 2 transformers (460x115 and 460x230). The neutral of our transformers is usually wired to a 'neutral' terminal and also grounded to the backpanel. Is there any issue with both transformer neutrals being grounded to the backpanel, thus both voltages...
We use immersion heaters in piping and some customers have experienced issues with the fuses blowing. We typically have 30kW heaters (@460VAC), for a load of under 40A and use 50A high-speed style fuses (Bussmann FWP series). It certainly seems as though it's an operator issue, since we don't...
Just wondering if anyone has come across this. We have a basic motor control panel for a 7.5HP motor (460VAC, 3phase). The protection is a motor protection circuit breaker, rated/sized according to the motor. We tested it without issue and the customer is now claiming that they are 'blowing out...
I'm trying to figure out the amount of current on each phase in an electric heater. The heater is 24kW @ 460VAC, which calculates to about 30A. The dual-phase contactor we are looking at using is rated for 25A per phase, and the engineer with the company said that the 30A load is divided equally...
i have a circuit that i need to switch between a couple different voltages to give an E/P 0-5V controller. right now, i am planning on using a 5VDC supply wired to two different resistors and a 2 position switch (to select either resistor), in order to feed the E/P with two different voltages...
i had planned on having a valve control unit that used 24VDC PNP proximity switches built into it to sense when the valve opens and closes (wired back to an AllenBradley 'sinking' PLC input card). our purchasing manager cannot get the control unit with a PNP switch in the timely fashion he wants...
For UL508A purposes, we typically run any non-UL listed devices on our 120V systems through a GFCI receptacle. We have a project where we are using 230V and our standard GFCI receptacle is only rated for 125V. I'm guessing I need a 6-20R receptacle configuration with a GFCI, but cannot find...
We are using external door-mounted outlets on a control panel for our system, they are non-GFCI general use receptacles. A customer has asked us to wire the power for these outlets from the GFCI receptacle within the control panel, in an effort to "make them a GFCI". Since the reset button...
I have a formula that was given me for determining the required surface area of an enclosure, but I'm curious if anyone else has seen it or knows where I might be able to find it. I want to make sure I can show a legitimate source for it should anyone request more info on my calculations...
i normally use contactors and motor circuit protectors together to form a self protected motor controller (so as to follow UL508A and eliminate the need for additional fuse protection). i've also seen this listed as a 'TYPE E' motor controller...does a type e motor controller mean strictly that...
A customer asked us to make sure our panels are Arc-Flash Compliant, and if they aren't - they told us we need to use a divider between the 480V and 120V circuitry. We've never had to deal with this issue, how/where can I find info on proving that our panel would be Arc-Flash compliant? Is it...
We're looking at replacing our control panel wiring (MTW wire) with THHN wire - which we already use in our conduit wiring. Does anyone know of a website that easily explains the differences between the two so that I can give my boss something to read to help him decide?? thanks in advance.
I'm looking for a list of standard abbreviations for industrial systems regarding cleaning in the pharmaceutical and food/beverage fields. Mechanical or electrical related abbreviations would be of great help.
