QUESTIONS re: MEGA-WATT 33-AMP POWER SUPPLY
This critter can be found on eBay. It is a switching type power supply. Supposed to have an ultimate amperage potential of 33, voltage adjustment of 10, to 15, and work fine as a long term battery ...
Forum Discussion
Paralleling by design means that the two power supplies can 'talk' to each other and balance their output so they share the load pretty much evenly. One of the power supplies I designed for some telecom equipment, there was a load share line tied between the two dual feed supplies through the positronic connector on the backplane.
Again, I really doubt these power supplies are 4 quadrant types. All the worry about paralleling them - just give it a try. Those supplies look just like the MeanWell supplies I've used and they're not 4 quadrant - no worries about the other supply sinking the power to try and lower the other supply's output.
There may be overvoltage protection on this supply but VERY likely it does not scale with the voltage adjustment pot. In other words it's fixed.
PS. if you do use relays to switch resistances in and out of your circuit, switch them ACROSS an existing resistor value. What way your signal is never OPEN and depending on how you wire it could result in the output going very high. Relay contacts do go bad and having low current pass through them is actually bad if they're not designed to handle it. Low signal relays use gold contacts just for that reason.
By the way, MegaWatt and MeanWell are the same initials. I think MeanWell uses the same power supply part numbering too.
http://distributor.meanwellusa.com/webnet_usa/search/seriessearch.html
What may be a problem is the overcurrent protection. These supplies are not current limited and how they handle overcurrent protection may screw with your design. Some latch OFF until the power is removed and the supply's caps discharge to the reset voltage for the protection. If it gracefully tapers the voltage back - you're golden. You can use them as a constant current source to the max output until the Vset is reached at which point it's constant voltage.
If you do plan on isolating them from each other with blocking diodes - no need to worry about buying high speed ones. The voltage control circuit is not high speed - you're not getting the raw switching frequency out the output terminals.
Lastly, some supplies have Vsense leads to compensate for IR losses in the hookup leads. Doesn't look like your supply would have them, but if they did you could tie the Vsense to the output side of your blocking diode and that would automatically compensate for any Vdrop changes with temp.
Again, I really doubt these power supplies are 4 quadrant types. All the worry about paralleling them - just give it a try. Those supplies look just like the MeanWell supplies I've used and they're not 4 quadrant - no worries about the other supply sinking the power to try and lower the other supply's output.
There may be overvoltage protection on this supply but VERY likely it does not scale with the voltage adjustment pot. In other words it's fixed.
PS. if you do use relays to switch resistances in and out of your circuit, switch them ACROSS an existing resistor value. What way your signal is never OPEN and depending on how you wire it could result in the output going very high. Relay contacts do go bad and having low current pass through them is actually bad if they're not designed to handle it. Low signal relays use gold contacts just for that reason.
By the way, MegaWatt and MeanWell are the same initials. I think MeanWell uses the same power supply part numbering too.
http://distributor.meanwellusa.com/webnet_usa/search/seriessearch.html
What may be a problem is the overcurrent protection. These supplies are not current limited and how they handle overcurrent protection may screw with your design. Some latch OFF until the power is removed and the supply's caps discharge to the reset voltage for the protection. If it gracefully tapers the voltage back - you're golden. You can use them as a constant current source to the max output until the Vset is reached at which point it's constant voltage.
If you do plan on isolating them from each other with blocking diodes - no need to worry about buying high speed ones. The voltage control circuit is not high speed - you're not getting the raw switching frequency out the output terminals.
Lastly, some supplies have Vsense leads to compensate for IR losses in the hookup leads. Doesn't look like your supply would have them, but if they did you could tie the Vsense to the output side of your blocking diode and that would automatically compensate for any Vdrop changes with temp.
