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I am trying to run an old Motorola PTP 400 Orthogon with a WS-12-250-DC.

I have used a passive injector as a de-jector! The standard 240VAC Orthogon PIDU has an alternative 48-58VDC input to use as opposed to mains. So the POE output from the switch is running the radio quite satisfactorily using this setup.

The only issue is the radio is drawing a variable 25-40 watts off that port. Is this sustainable? Is it possible to parallel the power output of two ports?

Hopefully someone has tried this one before!?! Thanks In Advance!

A quick schematic so it is slightly more obvious!

Why not use a 48VH port which is capable of pushing 1.5A sustained if you're using all 4 pairs to draw the power.

The normal 48V ports are only rated at .75A or around 36-40 watts sustained at 55C because it only provides power on 2 pair.

You see the problem or limiting factor here is not only the Polyfuses that will trip when too much power is pulled at 55C but the the power is going through the Ethernet transformer which is only rated at a MAX of 1 watt sustained per pair. This is why our 48VH ports are rated at twice the amount of current as the 48V ports as the power is provided across 4 pairs instead of 2 pairs.

48V port @ .75A
Pins 4,5 (+) <- Only using 1 pair for positive
Pins 7,8 (-) <- Only using 1 pair for negative

48VH port @ 1.5A
Pins 1,2,4,5 (+)
Pins 3,6,7,8 (-)

The WS-12-250-DC has FOUR ports that support 48VH - Ports 1,2,3,4

If you pull too much current through any one pair you risk the polyfuse tripping which causes no damage but you can also burn out the Ethernet transformer by pulling too much current across a single pair especially when the switch is in a cool location as the Polyfuse trips at .75A @ 55C so in cooler environments the Polyfuse will not trip in time to protect the Transformer.

Now to pull power from all 4 pair you may need to make your own injector that pulls power from all 4 pair.

QUESTION: Can you combine power from 2 ports
ANSWER: yes so long as the injector or in this case dejector you're using is pulling the power off the pairs via a transformer with a center tap as you would not want to patch together the wire directly as this would be bad but I would suggest using a 48VH port

QUESTION: WIll the port sustain 24-40 watts
ANSWER: The transformer is rated to 1 amp or 48-50 watts per pair and the polyfuse is rated to .75A at 55C per pair so if your switch is not in a really warm location it could provide up to 48-50 watts sustained with no damage to the transformer.