Thread: electronic powder despinsers

Originally Posted by zimmer

If you read my post I am not proposing either device as a solution, I am saying they just won't run a small load at any rate. The weak point of the whole set up is the Switched Mode PS. It is pointless interposing other devices before the SM PS. The ultimate solution is probably a regulated battery supply. This same topic was hounded to death on the Oz F Class forum recently but more focused on protecting expensive digital scales rather than dispensers.

Actually a switch mode power supply is usually a lot better than the old transformer for voltage stability. It continuously adjusts output to compensate for load and input voltage so is very stable. Because they switch in the order of 40kHz it is easier to smooth out the resulting voltage requiring smaller components. They are not as reliable as a basic transformer but are very easy and cheap to replace. Either way the additional voltage regulation in the device will cope with either. Things that are likely to have a greater influence of repeatable accuracy will be temperature variations, draughts, vibrations/movement and static charge build up.

Originally Posted by gadgetman

Actually a switch mode power supply is usually a lot better than the old transformer for voltage stability. It continuously adjusts output to compensate for load and input voltage so is very stable. Because they switch in the order of 40kHz it is easier to smooth out the resulting voltage requiring smaller components. They are not as reliable as a basic transformer but are very easy and cheap to replace. Either way the additional voltage regulation in the device will cope with either. Things that are likely to have a greater influence of repeatable accuracy will be temperature variations, draughts, vibrations/movement and static charge build up.

Heh gadgetman thanks for the electronics lesson but for the last 30 years I have worked in heavy industry responsible for small DC drives thru to 10,000HP DC drives plus their other associated control systems. The older drives were all modular discrete components a lot of which I could fault find to component level, so I do know a transistor when I see one or how a very basic device like a SM PS works. Incidentally, on my Chargemaster I have gone back to using the original wire wound PS supplied with it after the super reliable SM PS partially failed.

Originally Posted by zimmer

Heh gadgetman thanks for the electronics lesson but for the last 30 years I have worked in heavy industry responsible for small DC drives thru to 10,000HP DC drives plus their other associated control systems. The older drives were all modular discrete components a lot of which I could fault find to component level, so I do know a transistor when I see one or how a very basic device like a SM PS works. Incidentally, on my Chargemaster I have gone back to using the original wire wound PS supplied with it after the super reliable SM PS partially failed.

As I said, SM isn't as reliable but they do regulate better and are cheap to replace.