MINAC Systems
Revision A
USER MANUAL
31 January 2005
63860.doc
© For reproduction rights, see cover page.
Page 31
6.3.3
Output Power
There are the following maximum output powers available for continuous use and
intermittent duty:
Equipment
Continuous use
Intermittent duty
MINAC 25/40, 25/40 Twin
25
40
MINAC 50/80
50
80
The maximum output powers are attainable only with low Q - magnetic steel.
The output power can be regulated by using the following three different parameters
(modes of operation):
AC current
Using the current to regulate the output power is recommended for
heating processes with varying impedance as a constant current
produces constant induction. Typical application: hardening.
DC power
DC power regulation is recommended for heating processes where
the load is constant (constant impedance) or in general where heat
absorption varies as a function of the heating temperature. This
mode of operation is generally chosen when the equipment is used
in a production line.
Temperature
Temperature mode can be used in special applications where a
temperature sensor is installed at the workpiece. This also requires
optional temperature input connector.
In local operation, the setpoint can be either entered as a percent value in a
sequence program or adjusted by using the “up” and “down” arrows.
NOTE:
As long as a POWER ON signal is given, the output
power will never be zero, although the reference setpoint
may be set to zero. There will be a small current in the
coil because the frequency converter's regulation system
needs some current feedback to function.
6.3.4
Distance to Workpiece
The efficiency of the coil decreases as the distance to the workpiece increases. The
best results are obtained where the distance between coil and workpiece is 1-3 mm.
Practical reasons, such as the shape of the workpiece, may require a larger air gap
between the coil and the workpiece, although this may reduce efficiency.