MT5F37311
© Fuji Electric Co., Ltd. All rights reserved.
9
Torque
Sequence
Initial
1/3 of specified torque
(1)
→ (2) → (3) → (4) → (5) → (6) → (7) → (8)
Final
Full specified torque
(8)
→ (7) → (6) → (5) → (4) → (3) → (2) → (1)
6.4 Flatness of fastening part
The flatness of the fastening portion of the module is specified in the specification. In addition, the
following values are recommended for the system flatness at the module area.
System flatness at the module area :
≦
50μm
Exceeding the requirement above may lead to damage of the power module.
6.5 Parallel connections
In high capacity inverters and other equipment that needs to control large currents, it may be
necessary to connect IGBT modules in parallel. When connected in parallel, it is important that the
circuit design allows for an equal flow of current to each of the modules. If the current is not balanced
among the IGBTs, a higher current may build up in just one device and destroy it. The electrical
characteristics of the module as well as the wiring design, change the balance of the current between
parallel connected IGBTs. In order to help maintain current balance it may be necessary to match the
V
CE(sat)
values of all devices.
Also, when the IGBT module has the cooler with the water jacket, it is necessary to adhere strictly to
specifications such as water temperature, water flow and pressure within each water jacket.
For more detailed information on parallel connections, refer to the application manual for IGBT
module.
Fig. 8 Screw sequence for IGBT module
(7)
(3)
(1)
(5)
(8)
(4)
(6)
(2)
6.3 Prohibited matters:
(1) Excessive tightening torque: IGBT module shall not be used anymore.
Cause of cooling system destruction by deformation of the aluminum cooler and buckling of
the stud.
(2) Insufficient tightening torque:
Liquid leakage from the cooling flange may occur, or the screws may be loosened
during operation, cooler destruction due to vibration during operation are expected.
(3) Applying a load onto the cover of the cooler:
Cause of cooling system destruction, cooling water leakage are expected.
