Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
09/21/10 08:00
Read: times


 
#178619 - Crest factor/power factor correction
Responding to: ???'s previous message
One other thing - what does the applicable regulations say for your market, and for this type of equipment/power range?

One important thing is that the power companies doesn't too much like loads that either phase-shifts current and voltage, or that have high crest factors. If current is only drawn for short parts of the half-period, you will get high crest factors, since the difference between the maximum current drawn and the effective current needed to produce the same amount of power will greatly differ.

When you have switched to regulating using full half-cycles, your power factor and crest factor will be nice since you basically have a nice resistive load.

But during the soft-start, where you only drive the header using parts of the periods, the peak current will be very much higher than the effective current. That is a reason why it may be advantageous to look at a resistive limitation of the initial current.

On more and more markets, the requirements for power-factor-corrected equipment becomes very important. And for smaller and smaller power consumers.

List of 41 messages in thread
TopicAuthorDate
What is the reason for Heater blowing.            01/01/70 00:00      
   Hof often/how we?            01/01/70 00:00      
      Some more information...            01/01/70 00:00      
   continuous rating            01/01/70 00:00      
      This could be the reason...            01/01/70 00:00      
   Way too much current...            01/01/70 00:00      
      Some more information required...            01/01/70 00:00      
   do you have hysteresis in your control?            01/01/70 00:00      
      No there is no hysteresis.            01/01/70 00:00      
         Four pulses?            01/01/70 00:00      
            The Heaters are failing, electronics is OK.            01/01/70 00:00      
               Why Pulses?            01/01/70 00:00      
                  I will do just that...            01/01/70 00:00      
                     Processor must know about zero-crossings            01/01/70 00:00      
               ??            01/01/70 00:00      
                  soft start            01/01/70 00:00      
                     Soft Start            01/01/70 00:00      
                        an easy and interesting check            01/01/70 00:00      
                           Soft start, again...            01/01/70 00:00      
                  Yes these heaters need Soft start            01/01/70 00:00      
                     Again: Power? Voltage? Current?            01/01/70 00:00      
                        Avoid driving gate all the way to next zero crossing            01/01/70 00:00      
                           Crest factor/power factor correction            01/01/70 00:00      
                     Phase angle control...            01/01/70 00:00      
                        I agree with you.            01/01/70 00:00      
                           Good luck!            01/01/70 00:00      
                           are all heating coils the same ?            01/01/70 00:00      
                           There You Go            01/01/70 00:00      
         re the possible need for hysteresis            01/01/70 00:00      
         Power? Voltage? Current?            01/01/70 00:00      
   Alternate Heating Control Algorithm            01/01/70 00:00      
      Some more clarification...            01/01/70 00:00      
         Voltage - or power? [ed]            01/01/70 00:00      
   The other controllers            01/01/70 00:00      
   Thanks All members.            01/01/70 00:00      
   just suggest..            01/01/70 00:00      
      Reply to JecksonS Ben            01/01/70 00:00      
         Good point!            01/01/70 00:00      
            supposed to            01/01/70 00:00      
         opto isolated triac            01/01/70 00:00      
   My solution            01/01/70 00:00      

Back to Subject List