2012年9月12日 · The utility provides the site with a 480V single phase service. The Owner has an existing 480V transformer that gets the voltage down to 120V. This xfmr is being relocated, specs on it are: 15kVA, 60Hz, single phase, Primary Volts 432/456/480, Secondary Volts 120/240. See attached photo which includes a wiring diagram - not sure what to make of it.

2018年12月27日 · This is my first time installing a transformer of this type. I know I have to bond my XO in your most common 480 delta stepped down to 120/208 wye but not sure about if I have to bond what is the X3 (or X4, they’re connected) terminal which is where my neutral is landing.

2022年2月9日 · I have 15kVA dry type 480V single phase to 240/120V single phase transformer. Following: 1. Does the primary breaker protect the secondary conductors or does it need to have secondary main breaker? 2. Is the transformer separately derived need grounding electrode or not? 3. Would rules of 450 apply sizing primary breaker and secondary breaker?

2019年3月13日 · You need to look at wiring diagrams for 240/120 3-phase 4-wire connections. This system often goes by several slang name, a popular ones are 'wild-leg' and 'high-leg'. Before we go off into the weeds: what loading will you require? How much 3-phase 240V?, How much single phase 240V, how much single phase 120V?

2008年8月13日 · Consider an ordinary residential 120/240V single phase service. You have _3_ wires that come from the transformer, and you supply your loads with various combinations of those three wires. One of those wires is the neutral, and it is _intentionally_ connected to ground, and is called the 'grounded conductor' or 'neutral'.

2008年2月25日 · If you only need 120/240V single-phase, there is no reason to pay for and install the 3-phase transformer. Connect 480V 2-wire to a 480-120/240V single-phase transformer. Warning: a VFD will generate "50Hz" for a motor but it will be all chopped up and distorted, not a neat sine-wave.

2015年11月20日 · Can you please provide NEC section or some sizing instructions on how to size for transformer and primary side wiring: Primary Source Specs:-coming from our MCC-480V 3 phase 60HZ Secondary Load - See attachment-120/240V Single phase 60 …

2011年1月31日 · A single 480-volt phase wire and a neutral would give you 277-volts unless it is a corner grounded system, just as on a 120/240 volt system one phase conductor and the neutral give you 120 volts. With a 480 volt single phase you would need two hot conductors (ungrounded conductors) and a grounding conductor - no neutral required.

2014年3月10日 · I have a control transformer which has 480v 3 phase primary-120v single phase secondary. For some reason, the wiring diagram doesn't make sense to me. Being that it is a transformer, it is a separately derived system. I have always derived my grounded conductor from the XO bond to my GE. Not to mention the wiring diagram doesnt make any sense.

2015年9月13日 · The wiring schematic is in the attachment in the OP.[/QUOTE] The only other thing that may confusing is applying the HV taps to adjust for a voltage higher or lower than 208. Reconnecting that jumper toward the lower portion of the coils is what I' m referring to in order to assure that you get as close to the 120/240 sec voltage as practical.