Can we eliminate the harmonics by using the online UPS? this question raised when we designing the power provision for X-RAY or any radiology eq, part of the clients request not only because of the interruption time but also for improving the input sine wave to the eq. I understand the 12 steps inverter could do but what about the old 6 step?
Harmonics when using UPS
- Thread starter m sleem
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Modern UPS units have an IGBT PWM inverter output with a fairly low harmonic content.
But, can we get better characteristics after using the UPS compared to the provision without UPS?
It depends on how bad the supply is in the first place.
From your opinion i understand that in terms of harmonics the ups is not a harmonic filter, so the client is mistaken when asking to improve the input characteristics by using the UPS.
It is not intentionally a harmonic filter but, since it generates it's own regulated sine wave output it does not send the load the input sine wave. From memory I've seen figures of 2-3% for voltage stability and similar for harmonic voltage distortion.
If your supply is worse than that a UPS could be an improvement.
junkhound
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- Renton, WA
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- EE, power electronics specialty
The input of a good xray (or any other high einergy power supply should have a power factor correction boost circuit (PFC) that eliminates the effect of the lower input harmonics.
UPS vary from a quasi sine wave (2 or 3 superimposed square waves) to true sine wave based on 50 kHz or higher pulse width modulation (PWM) control circuits.
Ans to your basic question thus is: Could be anywhere from no improvement to total elimination of harmonic effects;
it depends on the Xray equipment power supply and the UPS output algorithm.
ghostbuster
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- Great White North
Limited inrush current capability out of the ups to the Xray machine maybe a bigger problem
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