50Hz 24vac less power?
50Hz 24vac less power?
(OP)
By putting 208v on a 200v primary/24v sec. transformer (250VA) I get 25v @ ~10 amps. I put a bridge rectifier on the output and get roughly 22V, which is fine. If my input voltage is 50Hz rather than 60Hz, is the power output reduced any?
In addition to several LED's, my main load is (4) 24VDC solenoid valves with a 1.3A rating on them, with varying duty cycles....for testing, maybe 50%.
I'm guessing my 120 "lumps" being reduced to 100 'lumps' would not be significant enough as seen by the valves to make a difference, but I've got a ghost in the machine...
I noticed that the failure occurred when it was cooler outside, which I figured meant the valve had to work harder to 'warm up', in addition to the hydraulic fluid being cooler, therefore slightly more viscous (although our ME thinks the viscosity is not changing much-not that big of an ambient temp difference....10-15 deg. F)
Lastly, I was thinking maybe after the initial firing of the valves, they may have built up a field that had to be overcome (back EMF) on subsequent firings.
All this considered, why would there be NO problem 95% of the time??
In addition to several LED's, my main load is (4) 24VDC solenoid valves with a 1.3A rating on them, with varying duty cycles....for testing, maybe 50%.
I'm guessing my 120 "lumps" being reduced to 100 'lumps' would not be significant enough as seen by the valves to make a difference, but I've got a ghost in the machine...
I noticed that the failure occurred when it was cooler outside, which I figured meant the valve had to work harder to 'warm up', in addition to the hydraulic fluid being cooler, therefore slightly more viscous (although our ME thinks the viscosity is not changing much-not that big of an ambient temp difference....10-15 deg. F)
Lastly, I was thinking maybe after the initial firing of the valves, they may have built up a field that had to be overcome (back EMF) on subsequent firings.
All this considered, why would there be NO problem 95% of the time??





RE: 50Hz 24vac less power?
Viscosity may be a problem with some AC powered valves but should not affect DC valves.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 50Hz 24vac less power?
RE: 50Hz 24vac less power?
Benta.
RE: 50Hz 24vac less power?
RE: 50Hz 24vac less power?
RE: 50Hz 24vac less power?
Also with a transformer output of 24V you should have an unloaded voltage of about (24V x 1.41)- 2V = 31VDC
If you are seeing values like 17V,(once you account for incorrect input voltages), you have rectifier or transformer issues.
Keith Cress
kcress - http://www.flaminsystems.com
RE: 50Hz 24vac less power?
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If we learn from our mistakes I'm getting a great education!
RE: 50Hz 24vac less power?
The lesson here was that at 50 Hz, the mechanical speed was faster than the pulsed supply voltage. Some cap is needed. A 470uF 50V Is likely large enough to solve the problem. Your transformer is likely rated 240V and is not saturating yet. Adding a capacitor will likely solve your problems.
RE: 50Hz 24vac less power?
RE: 50Hz 24vac less power?
For example, transformer may be rated at 100V 50Hz/ 120V 60Hz, or the same transformer may be rated at 100V 50/60Hz.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: 50Hz 24vac less power?