Operator’s Manual Series 300 Automatic Transfer Switches G design, 1000 through 3000 amp. sizes TABLE OF CONTENTS section DANGER is used in this manual to warn of high voltages capable of causing shock, burns, or death. INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . 1 SEQUENCE OF OPERATION . . . . . . . . . . . . . 2 TESTING & SERVICE . . . . . . . . . . . . . . . . . . . . 3 WARNING is used in this manual to warn of possible personal injury. ADJUSTMENTS . . . . . . . . . . . . . . .
Nameplate Catalog Number Identification The Transfer Switch nameplate includes data for each specific ASCO Series 300 ATS. Use the ATS only within the limits shown on this nameplate. G300 Neutral B – switched C – overlapping blank – solid Phase Poles 2 – single Ø 3 – three Ø 3 A typical Catalog Number is shown below with its elements explained.
SECTION 1 INSTALLATION Auxiliary Cable Box for 1000–2000 amp ASCO Series 300 Automatic Transfer Switches (ATSs) are Listed under Underwriters Laboratories UL 1008 Standard for Safety for Automatic Transfer Switches. Series 300s are also Listed under CSA C22.2 No. 178 Standard for ATSs. All control features are UL Component Recognized, which assures that ASCO automatic transfer switches meet OSHA Safety Requirements and will be acceptable to electrical inspectors.
INSTALLATION (continued) Controller Ground Harnesses A grounding wire must be connected to the controller’s lower left mounting stud. Because the controller is mounted on the enclosure door, a conductive strap must be used between the enclosure and the door. This connection provides proper grounding which does not rely upon the door hinges. The transfer switch is connected to the left side of the controller by a plug–in harness (two plugs).
INSTALLATION (continued) Functional Test The Functional Test consists of three checks: manual operation, voltage checks, and electrical operation. Turn counterclockwise to Emergency. Turn clockwise to Normal. Do these checks in the order presented to avoid damaging the automatic transfer switch. slide hub onto shaft Read all instructions on the Wiring Diagram and labels affixed to the automatic transfer switch. Note the control features that are provided and review their operation before proceeding.
INSTALLATION (continued) observe these lights Figure 1–5. Standard controls and indicators. 2 – Voltage Checks Close the normal source circuit breaker. The Normal Transfer 1 Switch Position and the Normal Source Accepted lights should come on. First check nameplate on transfer switch; rated voltage must be the same as normal and emergency line voltages. Verify that the feeders have been connected to the proper lugs.
INSTALLATION (continued) observe these lights press this button Figure 1–6. Standard controls and indicators. 3 – Electrical Operation The normal source must be available and the generator 1 must be ready to start. Check that the Normal Source Accepted light is on. This procedure will check the electrical opertion of the Automatic Transfer Switch. Press and hold the Transfer Test button until the engine starts 2 and runs. This should happen within 15 sec.
SECTION 2 SEQUENCE OF OPERATION Lights show position of transfer switch. Transfer To Emergency The sequence for load transfer to emergency source begins automatically when normal source voltage falls below the preset dropout point or when Transfer Test button is pressed. An under voltage condition on any phase of the normal source is detected by the sensor. Lights show the sources accepted. Light for built–in engine exercise timer: ³ blinks rapidly when button is held 5 sec.
SECTION 3 TESTING & SERVICE PREVENTIVE MAINTENANCE DISCONNECTING THE CONTROLLER For high reliability and long life for the ATS: The harness disconnect plugs are furnished for repair purposes only and should not have to be unplugged. If the controller must be isolated, follow these steps carefully. Operate the switch at least once a month. Perform this 4–step Electrical Operation Test (test with load transfer). Disconnecting the Plugs Do not unplug the controller until step 1a. or 1b.
TESTING & SERVICE (continued) MANUAL LOAD TRANSFER 1. Open normal and emergency source circuit breakers. This procedure will manually transfer the load if the controller is disconnected. 2. Use the maintenance handle to manually operate transfer switch to the opposite source. See page 1–3, Manual Operation Test. Do not manually operate the transfer switch until both power sources are disconnected: open both circuit breakers. 3.
SECTION 4 ADJUSTMENTS Time Delay Adjustment To change a setting, follow procedure on page 4-2. Use Table 4-1 as a guide to time delay values and their corresponding adjustment DIP switch or potentiometer. Standard time delays are set to customer specifications (if none specified, standard factory settings are used). Table 4-1.
ADJUSTMENTS (continued) cover Do not make any setting changes while the controller is energized. thumb latch How to Change a Setting 1. Prevent the transfer switch from operating by disconnecting one source first, then the other, as follows: a. b. hook on left side If the transfer switch is in the Normal position, open the emergency source circuit breaker. Turn the engine starting control to off. Then open the normal source circuit breaker. Figure 4-1. Controller cover latch.
SECTION 5 CONTROL FEATURES – ENGINE EXERCISERS These timers periodically exercise the emergency engine-generator plant. They can be set to exercise with or without load transfer, or they can be completely disabled. The engine-generator should be exercised under load once a week for a minimum time period of 20 minutes, or follow the recommendations of the engine-generator set manufacturer. Refer to page 4–2 for location of DIP switches, battery (provided), and jumper block in the controller.
CONTROL FEATURES (continued) Optional Accessory 11BG – SOURCE AVAILABILITY SIGNAL & PROGRAMMABLE ENGINE EXERCISER MODULE 2–line display connections for source availability signal contacts 3 buttons Figure 5–2. Accessory 11BG module (mounted behind operator interface and connected to the controller) includes source availability signal contacts and a programmable engine exerciser.
CONTROL FEATURES (continued) How to Set Optional Programmable Engine Exerciser (part of Acc. 11BG module) Hazardous voltage capable of causing shock, burns, or death is used in this transfer switch. Deenergize both Normal & Emergency power sources before programming the exerciser. Use the UP and DOWN arrow keys to move through the displays.
CONTROL FEATURES (continued) INPHASE MONITOR FOR MOTOR LOAD TRANSFER LOAD DISCONNECT FEATURE Inphase monitoring logic controls transfer and retransfer of motor loads, so that inrush currents do not exceed normal starting currents. It avoids nuisance tripping of circuit breakers and mechanical damage to motor couplings. The Motor Load Transfer feature is built into the controller. DIP switch S1 (actuator 5) activates this feature: right = ON, left = OFF.
CONTROL FEATURES (continued) OPTIONAL STRIP HEATER (Accessory 44) Accessory 44 Strip Heater is designed to keep ambient temperatures within the Automatic Transfer Switch enclosure at acceptable levels. This accessory consists of a mounting bracket with strip heater, thermostat, and terminal block. A transformer with fuses is included when the power for the assembly is derived from voltages above 120 V ac. The 120 V ac customer powered assembly does not include a transformer.
A accessories, 5–2, 5–5 auxiliary circuits, 1–2 B battery, 4–2, 5–1 buttons, push, 3–1 bypass time delay, 1–5, 2–1, 3–1 C G INDEX ground, controller, 1–1 installation, 1–1 DIP Switches, 4–1, 4–2, 5–1, 5–2, 5–4 E electrical operation, 1–5 engine exerciser, 5–1, 5–2, 5–3 engine starting contacts, 1–2 F features, see control features frequency, pickup and dropout settings, 4–1 functional test, 1–3, 1–4, 1–5 Printed in U.S.A.
