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New Synchro 250dx....Old question

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  • New Synchro 250dx....Old question

    I ordered a new 250dx and need to know about breaker size.About the highest I will run the machine is 250amps@68En.I figure the draw will be about the same as 270 balanced or so. If I run a 100amp breaker will the machine kick off first?Or will the breaker trip in panel box.I obviously want machine to trip first,leaving fan on.My present wire is #6 TEC armoured cable which I feel will run the 100amp Ok,but if I need a 125amp breaker I will run a bigger cable.Anyone have any experience on this?


  • #2
    Don't know if you have the manual yet.

    Page 30 shows the electrical service recommendations.
    125A is the Max recommended circuit breaker for 220V input without PFC.
    Minimum input conductor is 6 AWG wire

    With PFC the breaker is smaller, 90A for 220V input and 80A for 230V input voltage.
    Minimum input conductor is 8 AWG wire

    Page 13 shows the input current for single-phase 60Hz.
    It makes a pretty good difference if your model has Power Factor Correction (PFC) built in or not.

    At 250Amps AC balanced- 40% duty cycle at 230V input the Current input is as follows:
    No PFC - 96A - (2.8A while idling)
    With PFC - 71A - (49.5A while idling)

    Hope that helps.
    Last edited by clint738; 02-15-2013, 04:25 PM.