PDU for high amp 48Vdc

Thu Jan 29 03:21:25 UTC 2015

The rotary actuators are an off-the-shelf item for transfer switches.  No problem to get them paired with high-amperage switches. But a contactor, which is a solenoid-driven switch, is also an off-the-shelf item. The ones I use in EV applications are rated for 1000A, and cost about $300.  You need to be careful to look at the trade-off between voltage, amperage, and the per-cycle probability of a weld, though.  An over-rated contactor helps a lot if you're going to be cycling it a lot, whereas if it's for emergency use only, you can hew a lot closer to the max rating. 

                -Bill

> On Jan 28, 2015, at 18:40, Robert Drake <rdrake at direcpath.com> wrote:
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> For larger DC devices with ~50amps per side, does anyone have a software accessible way to turn off power?
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> I've looked into PDU's but the ones I find have a max of 10amps.
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> I've considered building something with solenoids or a rotary actuator that would turn the switches on or off, but that's a complete one-off and would need to be done for each device we manage (not to mention it involves janky wiring all over the place I've got to explain to the colo)
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> My use case is pretty infrequent so it needs to be remote-hands cheap.. it's for emergencies when you need to completely power cycle a redundantly powered DC device.  The last time I needed this it was because a router was stuck in a boot loop due to a bad IOS upgrade and wouldn't break to rommon since it had been >60 seconds.  It came up again tonight because we wanted to disable one power supply to troubleshoot something.
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> FWIW, I believe I've seen newer Cisco gear with high-end power supplies that have a console or ethernet port which would possibly let you shut them down remotely.  That solves the problem nicely if you're dealing with only one bit of hardware, but I'd like a general solution that worked with any vendor.  Possibly a fuse panel with solenoids that could add/remove fuses when needed.. or would that be considered dangerous in code-ways or in telco fire regulation ways?
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