Motor loads, Long transfer times – Xantrex Technology ENERGY HW 1000 User Manual

Page 63

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Inverter Applications

975-0467-01-01

5–11

Motor Loads

Induction motors (motors without brushes) require two to six times their
running current on start up. The most demanding are those that start under
load (e.g. compressors and pumps). Of the capacitor start motors (typical
in drill presses, band saws, etc.), the largest you can expect to run is ½ to
1 hp (the transfer relays are rated at 2 hp.) Universal motors are generally
easier to start. Since motor characteristics vary, only testing will
determine whether a specific load can be started and how long it can be
run.

If a motor fails to start within a few seconds or loses power after running
for a time, it should be turned off. When the inverter attempts to start a
load that is greater than it can handle, it will turn itself off after a few
seconds.

Long Transfer Times

Xantrex has observed a specific situation where the

Freedom HW

may

take a long time to transfer to inverter mode when shore power fails -
maybe 0.1-0.2 seconds. This can occur when the

Freedom HW

is

powering motor loads where the motor is able to “freewheel” when power
is removed (e.g. a grinder). This long transfer may cause computers or
other sensitive equipment to operate incorrectly. If power glitches must be
minimized then Xantrex recommends that motor loads not be operated
when sensitive equipment is being used.

High Surge When Powering Incandescent and CFL Bulbs

A single incandescent bulb requires five to ten times its power rating
when lighting up from a cold start. If you have several bulbs lighting up
all at the same time, then the surge is even greater.

A Compact Flourescent Light or CFL also has a momentary surge that is
more than ten times its power rating when lighting up from a cold start.

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