Okuma OSP 5000 - Power Supplies

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Okuma America Corporation
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Rev. 8-21-01
This section will cover the basic construction of the electrical side of any Okuma machine tool
with a 5000/5020 series control. The various power supplies, the boards in the control rack and
in the EC I/O rack (mostly on M/C’s), and the different servo systems found on Okuma machine
tools with the 5000/5020 series control will be discussed.
Every Okuma machine tool comes with a set of electrical schematics and there is a “System
Configuration Sheet” at the beginning of these schematics which shows a basic electrical layout
of the machine. The system configuration sheet for some machining centers can be seen in the
maintenance manual for the machine in question. An example of a “System Configuration
Sheet” is shown on the following page.
Power Supplies
Most Okuma machines are designed to work on 208 volts AC incoming power. On some ma-
chines, a multi-tap transformer is standard. As a precaution, the incoming power and the taps on
the transformer should be checked before power is supplied to a newly installed machine.
As a precaution, the incoming power and the taps on the transformer should
be checked before power is supplied to a newly installed machine.
If more than one machine tool is connected to the same single power source, the “Power Source
Inductance” should be noted if power related problems start occurring. “Power Source Induc-
tance” can be obtained by dividing the value in the table by the number of machine tools con-
nected to the single power source.
Wiring inductance in 50 meters (164 ft ) of cable is approximately 12 µH when general cable is
used.
If the Power Source Inductance is too high, the following problems will arise.
• Deceleration time will be extended.
• During deceleration, the motor will generate noise.
• Transistor modules in the servo drives will fail prematurely.
VAC Unit
Applicable Motor Power Source Inductance
220V
Power Source Inductance
200V
37/30 kW to 55/45 kW
Less than 45
µ
H. Less than 115
µ
H.
22/18.5 to 37/30 kW Less than 70
µ
H. Less than 170
µ
H.
22/15 to 30/22 kW
Less than 110
µ
H. Less than 230
µ
H.
11/7.5 to 15/11 kW Less than 230
µ
H. Less than 480
µ
H.
Less than 7.5/5.5 kW
Less than 350
µ
H. Less than 850
µ
H.
D45
D30
D22
D11
D6