Hello All,
Long time lurker, first time poster. ET has been a great resource for the past decade. Thank you everyone for your thoughtful information.
I'm a mechanical vehicle engineer (Temple University, 2013) respectfully requesting a bit of electrical support.
I’ve taken a new role where I’m responsible for both the vehicle fleet and now the maintenance facility. I want to install an off the shelf Snap-On parts washer. It is a 230VAC, single phase, 60 amp machine. I have 480VAC three phase power and I’m looking to utilize a transformer, and/or possibly a converter to step down the voltage and convert it to single phase.
The shop has an 800 amp and 1,000 amp main breaker panels in the power distribution room, and I assume both are fed from the same supply. A power study was previously performed. The 1,000 amp panel was observed to have a peak draw of ~950 amps, but the 800 amp panel had a peak draw of ~225 amps. I will therefore have a “home run” fed to the machine on a dedicated circuit and breaker from the 800 amp panel. Transforming the 480, I expect to consume ~30 amps from the 800 amp panel. I’m looking for the best balance between cost and complexity. My concern is creating an unbalanced load, which may have undesirable heating/performance side effects to motors (HVAC, elevator, large vehicle hoist, etc) and other equipment being fed from the 800 amp panel.
Based on some limited research, the simplest, most reliable, and cheapest option would be to use a 15kVA single phase transformer, connecting two legs of the 480VAC on the input side. I understand there are other transformers (open delta and Scott T) that use all three legs, but still create an imbalance. I also understand it may be possible to use a three phase to single phase converter to avoid a load imbalance, but I suspect cost will increase and reliability will decrease. I planned to write a scope of work for an outside contractor to evaluate the options, propose a solution, and then test/document load imbalance on the 800 amp feed after the job if a transformer is used.
I've attached photos of the panel and load study.
Questions:
1. Since the supply to the 800 amp panel is likely very large compared to the load I need, using a single phase transformer should I be worried about creating a detrimental imbalance for other equipment being fed by both the 800 amp and 1,000 amp panel? Or is the load such a small percentage of overall supply, other equipment won’t effectively “see” the imbalance? Same question would apply for other two transformer types?
2. Would we be better off using a converter? What are the advantages/disadvantages?
3. Are there any other options that I have missed?
Thank you in advance for any thoughts or suggestions that you may have.
Long time lurker, first time poster. ET has been a great resource for the past decade. Thank you everyone for your thoughtful information.
I'm a mechanical vehicle engineer (Temple University, 2013) respectfully requesting a bit of electrical support.
I’ve taken a new role where I’m responsible for both the vehicle fleet and now the maintenance facility. I want to install an off the shelf Snap-On parts washer. It is a 230VAC, single phase, 60 amp machine. I have 480VAC three phase power and I’m looking to utilize a transformer, and/or possibly a converter to step down the voltage and convert it to single phase.
The shop has an 800 amp and 1,000 amp main breaker panels in the power distribution room, and I assume both are fed from the same supply. A power study was previously performed. The 1,000 amp panel was observed to have a peak draw of ~950 amps, but the 800 amp panel had a peak draw of ~225 amps. I will therefore have a “home run” fed to the machine on a dedicated circuit and breaker from the 800 amp panel. Transforming the 480, I expect to consume ~30 amps from the 800 amp panel. I’m looking for the best balance between cost and complexity. My concern is creating an unbalanced load, which may have undesirable heating/performance side effects to motors (HVAC, elevator, large vehicle hoist, etc) and other equipment being fed from the 800 amp panel.
Based on some limited research, the simplest, most reliable, and cheapest option would be to use a 15kVA single phase transformer, connecting two legs of the 480VAC on the input side. I understand there are other transformers (open delta and Scott T) that use all three legs, but still create an imbalance. I also understand it may be possible to use a three phase to single phase converter to avoid a load imbalance, but I suspect cost will increase and reliability will decrease. I planned to write a scope of work for an outside contractor to evaluate the options, propose a solution, and then test/document load imbalance on the 800 amp feed after the job if a transformer is used.
I've attached photos of the panel and load study.
Questions:
1. Since the supply to the 800 amp panel is likely very large compared to the load I need, using a single phase transformer should I be worried about creating a detrimental imbalance for other equipment being fed by both the 800 amp and 1,000 amp panel? Or is the load such a small percentage of overall supply, other equipment won’t effectively “see” the imbalance? Same question would apply for other two transformer types?
2. Would we be better off using a converter? What are the advantages/disadvantages?
3. Are there any other options that I have missed?
Thank you in advance for any thoughts or suggestions that you may have.
