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42 Freedom HF Owner’s Guide
Inverter Applications
The Freedom HF performs differently depending on the AC loads
connected to it. If you are having problems with any of your loads,
read this section.
Resistive Loads
These are the loads that the inverter finds the simplest and most
efficient to drive. Voltage and current are in phase (i.e. in step with
one another). Resistive loads usually generate heat in order to
accomplish their tasks. Toasters, coffee pots, and incandescent
lights are typical resistive loads. It is usually impractical to run
larger resistive loads—such as electric stoves and water heaters—
from an inverter due to their high current requirements. Even
though the inverter can most likely accommodate the load, the size
of battery bank required would be impractical if the load is to be run
for long periods.
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 1/2 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
A specific situation has been observed where the Freedom HF may
take a long time (~ 0.1–0.2 seconds) to transfer to inverter mode
when shore power fails. This can occur when the Freedom HF is
used to power motor loads where the motor is able to “freewheel”
when power is removed (for example, a grinder). This long transfer
may cause connected computers or other sensitive equipment to
operate incorrectly. To avoid this effect, it is recommended not to
connect motor loads together with sensitive equipment to the
inverter for power.
Freedom HF InvChg Owners Guide.book Page 42 Tuesday, April 29, 2014 12:10 PM