Connecting And Using The Coil - EFD MINAC 25 Twin User Manual

MINAC Systems
USER MANUAL
63860.doc
4

CONNECTING AND USING THE COIL

1. Make a good electrical contact between the coil and the HHT terminals — be
sure that the contact surfaces on both the coil and the HHT terminals are free of
dirt and oxides. If necessary, clean the surfaces with fine emery paper.
2. Be sure that the O-rings for the cooling water seals are free of any dirt or
damage.
3. When fitting the coil to the HHT terminals, maintain a parallel gap between the
coil and the HHT to avoid a short circuit.
4. Use only brass termination nuts on the HHT. Nuts of any other material are not
allowed. Torque the nuts to 9 Nm for 125S, and 14 Nm for HHT 240S and
HHT 400.
5. Once the flow of cooling water has been opened, hold the HHT so that the coil
points upwards. This prevents air bubbles from being trapped inside the
transformer, causing local overheating of areas which are not in contact with the
cooling water.
6. Prevent short circuits in the coil during operation by avoiding contact between
the coil and the workpiece. If contact is difficult to avoid, coat the coil with an
aluminum oxide (avoid oxide on the contact surface). This will reduce the risk of
short circuits. Coils supplied by EFD Induction a.s are already coated with an
aluminum oxide.
Figure 3. Separate HHT and Coil
© For reproduction rights, see cover page.
The HHT is a vulnerable part of the equipment and
therefore must be handled with care.
TEST RUN: When changing the induction coil or
heating new materials, run tests to check the
equipment settings.
Revision A
31 January 2005
CAUTION!
CAUTION!
Figure 4. Coil connected to HHT
Page 6