I have a 68volt rectified output that needs a bus capacitor of 7200uf , 91volt and 5amp ripple ,, if i can;t get the right size capacitor which way is it best to go, up or down in size (uf) derkiow
I have a 68volt rectified output that needs a bus capacitor of 7200uf , 91volt and 5amp ripple ,, if i can;t get the right size capacitor which way is it best to go, up or down in size (uf) derkiow
I work it out that at 68v a 7200µf will produce 5% ripple at ~4.4amps load.
at 10amps you would need around 16,000µf for 5% ripple.
It depends on your load and the amount of ripple you want to design in at max current.
One down side with going too large on capacitance is it requires an increase in transformer VA.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Hi derkiow
I just had a look at RS components
and found item 381 - 9194 8200 uF 100V 18A @ £34-45 screw terminals
with some values pcb mounting types are less expensive
if for some reason you need to use a number of capacitors to make up the required value
I would use 100 V capacitors in parallel that add up to the value needed
So is it safer to go up or down would 6600uf do or would i be better going to 8800uf .The reason i ask is that have some 2200uf capacitors already ,,,,and thanks for the replies derkiow
UP Always up. The more the better.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
i have three drives at 5amps so that will be 15amps and i have a 1kva transformer 45v @ 22amps my idea was to use 4 times 2200uf for each drive..derk
For a 15a max load at 68VDC you would need 25,000µf for 5% ripple.
100% rating would be 1.3kva and 60% duty cycle would require a .8kva supply.
So it looks like you could go up to 25,000 for 5% ripple.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.