Specifications
65
Soft Start
During the start-up process, the Scroll compressors use up
a very high amperage to produce the magnetic field need to
achieve the motor starting torque. This amperage loop is of
short duration, but can reach from 5 to 8 times the normal
operating amperage. As the motor accelerates, the amperage
decreases until it reaches the nominal value. These starting
loops cause interferences in the electric lines, and this could
affect the units connected to same.
The Soft Start accessory comprises an electronic starter
specially designed to limit the start amperage loop in single-
phase Scroll compressors.
Characteristics
- Two models available:
25 Amp (Models 5, 7 and 9)
32 Amps (Model 12)
- Limitation of the start current to less than 45 Amps.
- Self-adjusting control. Needs no adjustment at the job
site.
- Additional functions: Low voltage protection.
Rotor blocking protection.
Limitation of the number of starts.
- Substitutes the contactor.
- Specific design for Scroll compressors.
Operation
The starter should be connected to the signalling and power
lines, as shown in the following diagram. When the ON con-
tact of the signalling line closes, the control unit begins the
start sequence, keeping the amperage at less than 45 amps.
Meanwhile, it allows the motor to reach the sufficient torque
for a safe start. Both in the start as well as the stopping of the
motor, the thyristors withstand the motor current momentarily,
thus avoiding overheating of the mechanical contacts.
Motor protection
Both the current as well as the amperage the motor is sub-
jected to are monitored constantly by the starter, disconnect-
ing the system in the following cases of emergency:
- The motor does not start in a 0.8-second interval.
Example: The rotor is blocked.
- The amperage received by the system goes below 185 V
for over 1 second.
Timing function
The timing function protects the motor, allowing start-up of
same after a minimum of 3 minutes off time. In the case of an
emergency cut-out, this time is extended to 5 minutes so as
to let the motor cool off.
Status indication
The starter status is indicated by the flashing frequency of
a LED, and should be interpreted in accordance with the
frequency codes printed on the control unit casing.
Dimensions