| ??? 01/20/06 13:10 Modified: 01/20/06 13:14 Read: times |
#107874 - Storage cap Responding to: ???'s previous message |
U said:
Everytime machine will perform an operation current will go high as much as 13-15Amps for a second. and at some of the busy places the machine is doing at least 150- 200 operations a day in 8hour working time. With full wave rectification storage capacitor must provide all the current for a worst case duration of about 10msec. According to C = Q / U = I x t / U for a maximum voltage drop of 3V about 50000µF would be needed for the storage cap. This is no problem for a good toroid transformer. But needed current rating of transformer also depends on stiffnes of transfomer, not only on motor current being drawn from it. By other words, the transformer must be able to charge up the storage cap every 10msec additionally to delivering the motor current of 15A! For this it must be stiff enough. This is the reason why the current rating of transformer must be some higher than 15A. With a too weak transfomer the voltage drop at storage cap will be much much higher than the estimated value above. In any case you will need a soft start for the transfomer. Kai |
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typo | 01/01/70 00:00 | |
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