Laird Controls North America Inc. 818A ユーザーズマニュアル
Command Pro Engineered Systems
User Manual
User Manual
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6.3 Installation Wiring
Referring to the configuration sheet provided with the receiver (usually located within the receiver door),
dress the receiver output relay wiring and the control switch wiring along the inside wall of the enclosure.
This allows for easy troubleshooting and maintenance.
6.3.1 Receiver Power
Laird receivers are normally pre-wired for the most widely used control systems. Specific installations may
require rewiring the relay ‘commons’. When connecting the Laird receiver assembly to a power source that
has large amounts of interference (noise) generated by motors and/or contactors, use noise suppression
devices (snubbers) to prevent noise from triggering the receiver’s safety shut-down programming.
Never use the receiver case as a ground for other electrical equipment.
Never use the receiver case as a ground for other electrical equipment.
6.3.2 Relay Outputs
Limit the load current applied to the output relay bank ‘common’ to a maximum of 10 amps.
!
CAUTION
Connection to equipment or contractors with higher voltage or current requirements requires an
intermediate relay.
6.3.3 Output Snubbers
Snubbers are needed to suppress the noise generated from arcing relay contacts. When a contactor opens,
the contactor coil produces a large voltage potential much like automotive ignition systems. When the points
open on automotive ignition systems, the coil sends a large voltage to the distributor which jumps across
(arcing) the spark plug. The result is a large amount of noise generating in the system.
A snubber is a device designed to reduce arcing (noise). Laird uses a resistor capacitor combination to
accomplish this function. To prevent noise entering the receiver, it is recommended that all contactors
have snubbers installed directly across the coils. If more snubbers are needed, See
accomplish this function. To prevent noise entering the receiver, it is recommended that all contactors
have snubbers installed directly across the coils. If more snubbers are needed, See
6.4 Installation Procedure -21R14A Receiver
6.4.1 Power/Control Wiring
The transfer switch is wired so that the crane’s Main Line Contactor (MLC) is controlled by the radio MLC
relay when it is in the radio position and by the pendant controls when the switch is in the pendant position.
required unless there is a need for pendant operation. The switch can normally be wired without removing it
from the receiver cabinet. Any unused switch poles can be used for isolating additional functions.
!
WARNING
Before starting this installation, ensure that the crane power is disconnected and that all applicable
safety precautions are followed.
Use the following steps to install the wiring to the receiver board and/or control transfer switch: