| ??? 08/02/07 13:09 Modified: 08/02/07 13:28 Read: times Msg Score: +1 +1 Informative |
#142650 - the danger of using a voltmeter Responding to: ???'s previous message |
A rectifier-capacitor network only charges the capacitor during the peak part of the AC cycle. After that point, the load current discharges the capacitor until the next AC cycle peak. If you are measuring 270V DC on load, then that is the average voltage on the capacitors and there will be a 60V peak-to-peak ripple on top of the DC voltage.
an example of the danger of using a voltmeter, this question would never have been raised had you used a scope. Erik PS In most countries the circuit you describe will not be permitted because the current drawn from the AC supply is not sinusoidal. You will need to look at the relevant regulations, and I suspect you will need a PFC (power factor corrected) front end rectifier. A PFC circuit will usually limit inrush current to reasonable levels. whether 'legal' or not, do not make such a load without PFC. PPS just visuakize the almost nuclear event if the bridge recifier dropped 30V at 10A (300W) |
| Topic | Author | Date |
| Bridge Rectifier voltage drop | 01/01/70 00:00 | |
| Droop | 01/01/70 00:00 | |
| the danger of using a voltmeter | 01/01/70 00:00 | |
| Hidden voltage drops | 01/01/70 00:00 | |
| Its a three phase bridge rectifier | 01/01/70 00:00 | |
| Filtering or regulation | 01/01/70 00:00 | |
| also | 01/01/70 00:00 | |
| Unfortunately... | 01/01/70 00:00 | |
bridge can handle upto 60A | 01/01/70 00:00 |