Daktronics Scoreboard Dual Hoist - Manual (Page 5)

Theory of Operation 1
Section 1: Theory of Operation
Each Vortek hoist is connected to the main high voltage power buss through a safety twist-locking plug.
This plug brings in the main 208 or 480 VAC (refer to system riser), 3-phase power that is connected to
the motor contactors and motor brake located in each hoist assembly. The high voltage power originates
in the master control cabinet. Also connected to each Vortek hoist assembly through a safety locking
connector are 24-volt DC control and E-Stop circuit.
The reversing contactors control all movements of the hoist. Each S Series Vortek hoist with Push Button
Control runs in open loop and is controlled at the main Master Control Cabinet (MCC) via momentary
push buttons. Each hoist is protected via hardwired up and down control signals, hard struck limit
switches, emergency stop status and optional over/under capacity sensors. The up and down control
signals determine which contactor to energize for direction to run the hoist. The limit switches are used
for maximum up and down travel. The emergency stop status is used to detect the operation of the
emergency stop system and the optional over/under capacity sensors will insure that the hoist is being
operated within its designed capacity.
Housed within the MCC is a 24-volt DC power supply that powers the control circuit and the e-stop
circuit. A fused disconnect and a master control contactor are also mounted inside the master control
cabinet.
The 24-volt DC E-Stop circuit is connected to the E-Stop button located on the front of the MCC as well as
the E-Stop button located on the pendant, if applicable.