AC to DC Switching Power Supply

I received the following from technical support at AC Tech Lenze. He is looking at this as a backup generator that would turn on and off in certain circumstances. In your case this is our permanent power supply. Being that we do not sell generators I do not have a very good background in that area. By looking at the information below the main concern seems to be the phase to phase control coming from the generator. If the generator manufacturer can give you more detailed information on the output of the generator itself you would have to make sure we are getting what we need to maintain a smooth running AC drive/motor combination.

Although switching from line power to a backup generator is an accepted practice in many applications, there are some limitations you should be aware of pertaining to our Variable Frequency Drives. Many portable backup generators have a larger voltage swing on their phase to phase voltage input than our recommended phase to phase voltage tolerance which must be less than 2%. Although our AC Drives are equipped with surge guards in the input rectifier circuit, it may be necessary to use external protection for severe input disturbances such as surge arrestors. Larger variances cause greater ripple on the DC bus caps and this will damage them and other power components over time. Our drives need a minimum of 2 minutes between cycling of power. Otherwise it can damage the charge relay circuit or at the very least will blow the input fuses or trip the circuit breaker.

In cases where input power has “moderate” spikes in voltage which causes current surges, a 3% line reactor may help the situation.

Another solution is to add a voltage monitor with a suitable time delay. It has a protection trip level that shuts down in cases of under-voltage, over-voltage, a loss of phase and voltage imbalance between phases. This device ensures that our VFD will not see unbalanced input power or never be powered up until these other voltage tolerances and proper delay times are met.

M141000B AC Tech  100 hp 460 volt drive in a Nema 1 enclosure  $6,836.50

http://www.wolfautomation.com/Configure3.aspx?ProductID=23229&x=90&y=11

M141000D AC Tech 100 hp 460 volt drive in a Nema 12 ( oil tight dust tight) enclosure $7,473.40

http://www.wolfautomation.com/Configure3.aspx?ProductID=23229&x=90&y=11

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