Re: PDU for high amp 48Vdc

["Bill Woodcock" <woody () pch net>]

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 () direcpath com> wrote:
>
> For larger DC devices with ~50amps per side, does anyone have a software accessible way to turn off power?
>
> I've looked into PDU's but the ones I find have a max of 10amps.
>
> 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)
>
> 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.
>
> 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?