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Overload Relay
The adjustable thermal overload relay (OLR) provides overload protection for the motor in Drive and Bypass operating modes.
The bypass three-phase output power connection to the motor is made to the output terminals of the OLR. The OLR is set up
in the factory to be a manual reset device, requiring operator attention if an overload trip-out is experienced.
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Control Power Transformer
A Control Power Transformer (CPT) is provided to power the Z1000 Bypass 120 Vac control circuit. The VA capacity is
determined by the control circuit and optional functions specified for the unit. The CPT primary is fused in both legs, the
secondary is fused when required by NEC (transformer VA and wire size dependent). One side of the transformer secondary
is grounded to the bypass enclosure.
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Electronic Bypass Control Logic
Operating elements such as indicating LEDs, selector buttons, and control logic are incorporated into a PCB assembly to
eliminate the potential for loose wires after shipment.
The operating elements are located on PCB A3 and the control logic PCB A2 is mounted to the left-hand side of the enclosure
and contains the control circuit field wiring terminal blocks TB1 through TB5.
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Drive/Bypass Logic Interlocks
The Z1000 Bypass 120 Vac logic circuit is interconnected with the drive multi-function digital input terminals and multi-
function digital output terminals to allow a single customer interface to control both drive and bypass circuits. These drive
terminals are not available for field connections. All field control connections are landed at terminal blocks TB1 through TB5
on control logic PCB A2 and drive PCB A1.
1.4 Bypass Component Descriptions
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YASKAWA ELECTRIC SIEP YAIZ1B 01E YASKAWA AC Drive – Z1000 Bypass Technical Manual
