100v DC to low voltage (under 24V)

[han]

hi all,

Is there any simple efficient and save way to convert 100v DC to low voltage (under 24V)?
the device will be used to convert 100V DC supply in Electric power station to easy to used voltage (under 24V), and the power capacity needed is under 20VA.

I familiar with common dc to dc circuit (LM2576, MC60xxx, etc..) but the none of them capable to work at more than 60V.

I plan to use Industrial Switching Power supply, but aware low voltage brown out will reduce the lifespan of the power supply...

any suggestion are welcomed

thanks

[digsys]

Unless you want to make you own, or have a tight budget, these are what we use -
www.vicorpower.com/dc-dc-converters-board-mount/maxi-mini-micro-dc-dc-converters
Some have 4:1 IP range as well, all power levels, good efficiency.

[han]

thanks for reply,

yes, i have tight budget (under $100) since its only for trial and base on personal budged only...

is it possible to build or modify commercial  regular power supply?

[johansen]

Most laptop power supplies will have no problem operating from 100vdc, which corresponds to 71 vac, but they will not be able to deliver full rated load for various reasons (but 20 watts from a 90 watt converter should be easy). you might bypass the bridge rectifier to get 2 more volts into the device.

[digsys]

yes, i have tight budget (under $100) since its only for trial and base on personal budged only...
is it possible to build or modify commercial  regular power supply? 

Definitely. Have a look at the Meanwell AC-DC units. For what you want, you can find something well under $100.
Don't get Power factor correction, just plain AC in. The only thing you need to verify is the MIN AC in !!
For 100VDC, you need a minimum of ~70VAC_in (ideally 60VAC), so a computer P/Supply won't work.
Don't need to short out the bridge (AC>DC)
Edit: oops, forgot  www.meanwell.com/webnet/search/seriessearch.html