Backup Power Supply and Capacitor Start Motor

Er, would it be better to contact the respective manufacturers and get a warranty-based reply from them?

We are the manufacturer and thanks for the comment Please check my last reply for a little more information..hows the weather there?

Well, 500 watts should be enough for the motor (~330-350W needed). Given that the motor is a capacitor start it is likely single phase. What is GAXXs?

Double check that you actually have 500 watts, APC also gives a VA rating of 500 and a Watts rating of 300W on the same unit

Also, keep in mind that a 500W battery backup will only give you a minute or two of run time for a 1/3HP motor. These backups are intended to allow a grace period of power during an outage, for users to save their work and shut down their computers. If you really want a solution, and its a mater of life/death/health, I would have a gas/desiel powered generator on standby to power your medical devices in time of emergency.

I also agree with contacting the represenatives of the power supply companies to inquire about waranty issues.

I have a square wave 800VA (500W) APC square wave o/p ups which feeds 4 ceiling fans (single phase capacitor start each 60W), 4 fluorescent tube lights and a TV. With the 120Ah battery it is giving 4hours full load back-up. So back-up and running with capacitor start motors is not a problem with UPS. But based on functional criticality, I am with RVZ717 on his suggestion on genset.(some more loads can also be added) goodluck,

Is it possible that during start up of the oxygen generator, the motor is taking a hugh current ? This current is probably to big for the UPS.

A solution would be, connecting the UPS to a frequency converter. And than connecting the output from the frequency convertor to a three phase motor.

The UPS will supply the frequency converter and the frequency converter will start the motor very smoot; In this case you have a high starting torque for your oxygen generator and a low inrush current.

good luck

information given without any warranty.

Wow great suggestions and thank you to all.....The UPS is connected between the O₂ generator and an auto-start Diesel 5000KW Honda generator Set...In event that there is an emergency, as did occur 2 months ago in Boston Ma., after a power massive outage the Generator failed to start ....and there was not a backup power unit.

Our UPS inverter has Bluetooth ZigBee and RS232 I/O designed on board, as this product was originally designed for a much different application....So in the above situation, if the GENSET fails to start the UPS cuts in and then the UPS alert system I/O starts to call out to a 24 hour monitoring station.. In the Boston case there was a death of a young 19 year old man with Cerebral Palsy due to the failure of his O₂ generator after a power outage in the middle of the night..Our UPS Med Unit would provides that little extra margin of Safety..Thanks to all

Hope that helps..

Scotland forever

Peter macD

Typically, capacitor start motors still take 3-5 times full load running current to start. The increased starting torque and faster acceleration up to running speed (WORK) of a capacitor start motor MUST come from somewhere. Some applications need lots of starting torque. For instance, reciprocating compressors-large AND small, by their nature, have large cycles in torque requirements as they rotate from suction to compression strokes. The flywheel effect when they are up-to-speed reduces this torque peak tremendously if the rotational speed is allowed to vary some. STARTING a recip is much more problematic--a large flywheel smooths out running current draw--but increases start-up current needs--both magnitude and duration- of a 'direct across the line' motor. A 'smooth start' system uses either switched resistors to reduce current draw during start-up, or reduces the frequency of the power supply (and peak power draw of the motor.) Both reduce starting current draw, but switched resistors (lower voltage to the motor) lowers starting torque, which may not be enough to start a compressor. Reciprocating compressors need to be 'unloaded' to avoid the compression stroke power demand until the unit is up-to-speed and the flywheel effect is there. Long description for the question--buy a larger power supply.