Posted: 3/1/2012 4:02:22 PM EDT
|
We just got another CNC lathe in the shop, problem is we only have 220V 3 phase power and the lathe is setup for 440
The plate on the side of the machine reads "LOAD-48.0 KVA" We have a line on two transformers locally out of another shop, one is a 45 KVA and one is a 75 KVA. Will the 45 KVA be enough or is the 75 KVA what we need Thank you |
|
Go with the 75, you need to include the start load. Generally you size at 150% of FLA. Its almost always better to big big on the X-frmer. When its to small you get massive voltage drop and smoke.
KVA sizing always get confusing. Bigger better the extra carrying load isnt much |
|
Quoted:
We just got another CNC lathe in the shop, problem is we only have 220V 3 phase power and the lathe is setup for 440 The plate on the side of the machine reads "LOAD-48.0 KVA" We have a line on two transformers locally out of another shop, one is a 45 KVA and one is a 75 KVA. Will the 45 KVA be enough or is the 75 KVA what we need Thank you The 75kVA will be sufficient IF it's not feeding anything else. If it's feeding a panel, you need to determine the load on that panel to figure out how much, if any, spare capacity you have. Posted Via AR15.Com Mobile |
|
Quoted:
Quoted:
We just got another CNC lathe in the shop, problem is we only have 220V 3 phase power and the lathe is setup for 440 The plate on the side of the machine reads "LOAD-48.0 KVA" We have a line on two transformers locally out of another shop, one is a 45 KVA and one is a 75 KVA. Will the 45 KVA be enough or is the 75 KVA what we need Thank you The 75kVA will be sufficient IF it's not feeding anything else. If it's feeding a panel, you need to determine the load on that panel to figure out how much, if any, spare capacity you have. Posted Via AR15.Com Mobile No, just the single machine for now |
| Make sure you have sufficient power available and size the cables accordingly. The current on the primary side of the step up transformer is going to be roughly twice as large as that of the current at the machine. 75KVA three phase current at 220A is going to be around 200 amps. |
|
Quoted:
Make sure you have sufficient power available and size the cables accordingly. The current on the primary side of the step up transformer is going to be roughly twice as large as that of the current at the machine. 75KVA three phase current at 220A is going to be around 200 amps. What if we're not using all 75KVA? |
|
Quoted:
Quoted:
Make sure you have sufficient power available and size the cables accordingly. The current on the primary side of the step up transformer is going to be roughly twice as large as that of the current at the machine. 75KVA three phase current at 220A is going to be around 200 amps. What if we're not using all 75KVA? You could fuse it down, your asking for problems. 200amp 220volt in 100 amp 440 out more or less . Use proper sized conductors and then use smaller fuses if needed. Unless you have a long run its false economy to under size wiring. Start loads are problems with this stuff. I know a guys whos electrician undersized the wire, just sized for running, it would buzz and rattle in the conduit on start.... |
|
Quoted: Quoted: Make sure you have sufficient power available and size the cables accordingly. The current on the primary side of the step up transformer is going to be roughly twice as large as that of the current at the machine. 75KVA three phase current at 220A is going to be around 200 amps. What if we're not using all 75KVA? at the rated 48kva you are still looking at 130 amps. make sure you have the capacity and size wiring accordingly |