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<blockquote data-quote="TJ Cornish" data-source="post: 8977" data-attributes="member: 162">I&#039;ve used a Crown VRack a couple times now, and am at a loss to understand why they opted to put in a power selector switch. In &quot;208v&quot; mode, each of the three amps in the rack are fed phase to phase, so the amps each receive 208 v. In &quot;120v&quot; mode, the amps are fed from phase to neutral.The guy who owns the VRacks that I rent occasionally has asked if I have 208v power available, otherwise he&#039;ll set the switch to 120v mode. The amps have a universal power supply, and take 100 - 240v without needing to switch anything.The VRack is powered by an L21-30, which requires 208v power anyway, so there&#039;s really no &quot;120v&quot; mode short of making up an illegal cheater adapter with 3 Edison plugs to an L21-30R, so why would you ever want to be in &quot;120v&quot; mode? If you only had 120v power, you&#039;d be far better off unplugging the C19 cabling from the back and using external cables rather than bodging the distro.The only thing I can think of is behavior if you lose a phase - in 208v mode 2 amps go down, in 120v mode, you only lose 1 amp; the flip side is that if you lose the neutral, all 3 amps are floating. That seems like a pretty weak reason to not always use 208v mode.Any VRack aficionados know the real story? What am I missing?</blockquote>

[QUOTE="TJ Cornish, post: 8977, member: 162"] I've used a Crown VRack a couple times now, and am at a loss to understand why they opted to put in a power selector switch. In "208v" mode, each of the three amps in the rack are fed phase to phase, so the amps each receive 208 v. In "120v" mode, the amps are fed from phase to neutral. The guy who owns the VRacks that I rent occasionally has asked if I have 208v power available, otherwise he'll set the switch to 120v mode. The amps have a universal power supply, and take 100 - 240v without needing to switch anything. The VRack is powered by an L21-30, which requires 208v power anyway, so there's really no "120v" mode short of making up an illegal cheater adapter with 3 Edison plugs to an L21-30R, so why would you ever want to be in "120v" mode? If you only had 120v power, you'd be far better off unplugging the C19 cabling from the back and using external cables rather than bodging the distro. The only thing I can think of is behavior if you lose a phase - in 208v mode 2 amps go down, in 120v mode, you only lose 1 amp; the flip side is that if you lose the neutral, all 3 amps are floating. That seems like a pretty weak reason to not always use 208v mode. Any VRack aficionados know the real story? What am I missing? [/QUOTE]

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