ok, after a google search, I guess there are 208V clothes dryers commonly available. I was searching hard for a 208V well pump, but never could find one.
on a panelboard diagram, would you calculate the kva per leg as follows:
say a 208V single-phase dryer @ 20A
it would be 20A x 277V/1.73 =...
I see a lot of 240V equipment (water heaters, well pumps, AC, etc, but have never seen 208V single phase equipment. does most 240v equipment run on this stuff?
just curious, I have some used 208/120 (and 480/277) panelboards with 2 pole breakers.
other than for loads you would want to turn on simultaneously (lighting loads for example), I'm trying to think what sort of equipment, if any, would use that sort of power.
I am considering using a breaker for a motor short-circuit and ground-fault protection (standard thermal-magnetic sq.d FAL series) as per NEC 430.52.
I'm not sure if this is classified as an instantaneous trip or an inverse-time breaker. I downloaded the trip curves, but its not clear exactly...
is there a rule-of-thumb for estimating U value for a plate and frame heat exchanger for a given plate material and heat transfer area?
I have the basic details, but not the details of chevron angle, plate thickness, etc. I have downloaded the PHE software, but its difficult without all teh...
Any problems with this? The design calls for a Square-D LAL36400 400A breaker, The same breaker with shunt trip is available new for a lot less from an NOS supplier. I imagine the shunt circuit can just be ignored and it will function identical to the regular breaker?
right, that was my initial question, I would prefer to have simple push-button start stops at the motor location for safety and practicality, but this is not a disconnect as per code.
So I am looking at remote mounted lockable safety switch and remote starter, with a local pushbutton as a...
well, assuming the starter and safety switch are located remotely, what would be an acceptable local disconnect then? It appears that a listed lockout station ("system isolation equipment") is required.
further reading of 430.102(B) this would seem to fit well - "where such a location is impractical or introduces additional or increased hazards to persons or property".
Now I suppose it could be argued that the elimination of local disconnects is primarily for cost reasons, and that an...
I am trying to spec a disconnect/motor controller for the following motors, all are in class 1 div 1 group D, all are 480 3ph motors
(6) 1hp motor with start/stop only
(3) 10 hp motor with VSD
Since we are in a hazardous location, I am trying to consolidate equipment to save $$
looking at...
For an industrial facility, which has all equipment hard-wired, what is the required spacing of convienience outlets? These will be placed around the perimeter of the building for temporary maintenance loads such as tools, shop vacs, portable lighting, etc. The 12' spacing for residential and...
Is there anything inherently wrong with using a motor starter that is larger than required? For example, say a 1hp motor requires a 00 starter, but I have an extra size 1 starter laying around. Assuming I use the correct thermal elements sized according to the 1hp motor, I imagine it would work...
ok, so after reading that, I think I got it. Lets say I have a lighting load spread out as evenly as possible amongst the three phases. The single-phase currents are 3A, 2.5A, and 3.5A
calculate kVA per phase:
3 x 277/1000 = 0.83 kVA
3.5 x 277/1000 = 0.97 kVA
2.5 x 277/1000 = 0.69 kVA
total...
in a 480/277 delta circuit, should I use the 1.73 factor when calculating kVA from 277 lighting currents?
In other words when calculating KVA for a 480V motor load, the formula is V x A x 1.73 /1000
if I have 3 1A lights on three legs of a 480/277, is the kVA calculated by:
3 x 1 x 277 x 1.73...
the ugly's table shows starters being used all the way down to 1/2 HP motors. Anything below 2HP uses a '00' starter according to that table.
FWIW, I was thinking of using the circuit on pg 44.
