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1. General description
1.1 Features / applications
The LE-50PAU power amplifier is used to control the excitation current of the excitation coil for clutch / brake
such as powder clutch / brake, hysteresis clutch / brake, etc.
The power amplifier is applicable mainly to the winding / unwinding tension contorl for long-size material,
torque limiter for general machinery, etc.
The power amplifier si operative on wide range power source of 85VAC ~ 264VAC and is provided with con-
trol output of 24VDC, 4A or less anda aux. Power output of 10VDC, 2.0A, 10sec rating.
Main ffeatures
<Current / voltage contorl system >
• The clutch / brake may have resistance fluctuation of approx. 20% against the excitation coil tem-
perature fluctuation of 50
the exitation current not to contorl the voltage.
• The powe amplifier is designed as to be able to snsure the output current of 0~Imax against the
input sinal voltage of 0~Vmax. The input signal level ( Vmax ) is adjusutable to 0.5~8V, and the full-
scale output ( Imax ) to 0.2~4A respectively.
• For the closed-loop type control. the voltage control system is applicable without problem, as the
command input is compensated sutomatically even if any temperature fluctuation occurs in the
clutch / brake. (The adoption of current control system will be idealisitc for reduction of control error.)
• Particularly for the application in which the current distribution is adjusted by the variable resistor
with multiple clutch / brakes connected to one power amplifire, the use of voltage control method
will facilitate the adjustment operation.
The power amplifier is also disigned as to use the voltage control method for this purpose.
< Non-linearity compensation >
• The power amplifier is provided with such function as to compensate the non-linearity characteristic
of transmission torque of the excitation current for clutch / brake by 5-stage polygonal approxima-
tion, which can ensure the transmission torque proportional to the input signal voltage.
• The characteristic is an essential function for the open-loop type control, while it is also an essential
function for the closed-loop type control to reduce the control error, or to execute the internal taper
control.
• The internal taper control is such a control that the winding diameter is found by calculating it in-
versely from the output current ( or transmission torque ) to reduce the setting tension automatically
along with the increase of winding diameter.
< Built-in setting / display function >
• To allow the input signal level, output full-scale value, non-linearity data, etc. to be readily set, the
power amplifier is incorporated with a 4-digit / 7-segment display unit, 4 key switches and 10-pole
DIP switch.
• It is also possible to execute the inertia compensation or output monitor display, using this function
during baking.
°
C. Consequently, it is necessary for the open-loop type control to control
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