THREE PHASE WIRING FOR ASCO SERIES 300 AUTOMATIC TRANSFER SWITCHES RATED 30, 70, 100, 150, 200, & 230 AMPERES WITH GROUP 1 CONTROLS
Overview
This document provides detailed wiring diagrams, control features, and physical layout information for ASCO Series 300 Automatic Transfer Switches (ATS). These switches are rated for 30, 70, 100, 150, 200, and 230 Amperes and feature 'D' Frame, Group 1 Controls.
Control Features
Key control features include:
- Automatic transfer between normal and emergency power sources.
- Control of solenoid positions for transfer switch operation.
- Integration with engine exerciser and source availability signals (optional).
- Support for various neutral types: None, Solid Bus Plate, Switching, and Overlapping Contacts.
Wiring Diagrams and Circuit Descriptions
The diagrams illustrate the electrical connections for the transfer switches, including main power poles, operator circuits, and load terminals.
Main Power Poles and Load Connections
The system is designed for three-phase power. Terminals are designated as follows:
- Load Terminals: LA, LB, LC, LN (for Line Neutral)
- Normal Source Terminals: EA, EB, EC, EN (for Emergency Neutral)
- Emergency Source Terminals: NA, NB, NC, NN (for Normal Neutral)
The transfer switch (TS) facilitates the connection of the load to either the normal or emergency source.
TS Operator Circuit
The operator circuit manages the transfer switch's internal solenoids and controls. Key components and connections include:
- TS Terminals: A series of terminals (e.g., TS-1 through TS-72, TS-A, TS-B) connect to the control panel (CP) and other components.
- Control Panel (CP): Houses the primary control logic and interfaces.
- Optional Switching Neutral: A feature allowing the neutral conductor to be switched along with the phase conductors.
- Optional Overlapping Neutral: Another neutral connection configuration.
Control Contacts and Solenoid Positions
The transfer switch has control contacts that indicate the position of the solenoids, which in turn determine the source connection. A typical representation shows:
| TS Terminal Pair | Solenoid Position | Description |
|---|---|---|
| 6-7 | Closed Before | Normal Source Closed |
| 69-70 | Closed Before | Normal Source Closed |
| 8-9 | Closed Before | Emergency Source Closed |
| 71-72 | Closed Before | Emergency Source Closed |
Note: TDC (Top Dead Center) is specified for control cut-off (contact opening) setting.
Source and Load Circuits
The diagrams visually represent the three-phase connections for:
- Normal Source Circuits: Three phases (LA, LB, LC) and Neutral (LN) from the normal power supply.
- Emergency Source Circuits: Three phases (EA, EB, EC) and Neutral (EN) from the emergency power supply.
- Load Terminal Circuits: The three phases (LA, LB, LC) and Neutral (LN) supplying the connected load.
The ATS is shown closed on the Normal Source by default.
Wire Run Listing
The following table details the wire connections for the 30-230 Amp models:
| Wire No. | Connection From | Connection To | CLR AWG |
|---|---|---|---|
| 1 | TS-8 | P1-8 | 16 |
| 2 | TS-A | P1-15 | 16 |
| 3 | TS-6 | P1-2 | 16 |
| 4 | TS-3 | P1-4 | 16 |
| 5 | TS-B | P1-17 | 16 |
| 6 | TS-5 | P1-12 | 16 |
| 7 | TS-4 | P1-7 | 16 |
| 8 | TB-14 | P2-2 | 16 |
| 9 | TB-15 | P2-3 | 16 |
| 10 | TS-17 | P2-8 | 16 |
| 11 | TS-2 | P1-10 | 16 |
| 12 | TS-1 | P1-1 | 16 |
| 13 | TS-16 | P2-9 | 16 |
| 14 | TS-18 | P2-10 | 16 |
| 15 | TS-70 | P1-5 | 16 |
| 16 | TS-72 | P1-13 | 16 |
| 17 | TS-4 | TS-9 | 16 |
| 18 | TS-7 | TS-1 | 16 |
| 19 | TS-3 | TS-69 | 16 |
| 20 | TS-5 | TS-71 | 16 |
| 21 | TS-14 | TB-14 | 16 |
| 22 | TS-15 | TB-15 | 16 |
| 28 | CP-TB-4 | 11BG-TB-9 | 16 |
Note: ACC. 11BG refers to an accessory, likely the Engine Exerciser.
Physical Diagram and Components
The physical diagram shows the internal layout of the transfer switch enclosure and the operator interface.
Enclosure and Internal Layout
The transfer switch (TS) is viewed from the inside front. It contains the main power poles that connect to the normal source (EA, EB, EC, EN), emergency source (NA, NB, NC, NN), and the load (LA, LB, LC, LN). Terminals for control signals and connections are also visible.
Operator Interface and Controls
The operator interface typically includes:
- Operator Interface Membrane Assembly: Contains indicator lights and push buttons.
- Indicator Lights (DS):
- DS1: TS Connected to Normal
- DS2: TS Connected to Emergency
- DS3: Normal Source Available
- DS4: Emergency Source Available
- DS5: Engine Exerciser
- Push Buttons (PB):
- PB1: Bypass Time Delay
- PB2: Transfer Switch Test
- PB3: Set Engine Exerciser
- Optional Membrane Panel: For additional controls or indicators.
Control Panel (Group 1) and Accessories
The Group 1 Control Panel (CP) is a key component for managing the ATS operation. It connects via terminals like P1, P2, J1, J2, and CP-J4/P4. Optional accessories include:
- ACC. 11BG (Engine Exerciser & Source Availability Signals): Connects to the control panel for enhanced functionality.
- Optional Serial Communication Device: Allows for remote monitoring and control.
- Optional Switching Neutral: As mentioned previously.
- Heater: For environmental control within the enclosure.
- Bonding Strap: For electrical grounding.
A flat cable (PN 607761) is used for connecting the operator interface to the control panel, with a specific note for when ACC. 11BG is not used.
