Dual AC Power Source Transfer
Automatic transfer between preferred and alternate AC input sources using SCR switching and IPFD power sensing.
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3-Phase Static Transfer Switch for Dual AC Power Sources
The STS Series Three-Phase Static Transfer Switch provides automatic transfer between two independent AC power sources, with four models rated from 32A to 100A.
The STS Series is a three-phase solid-state switching device designed to transfer critical AC loads between a preferred power source and an alternate power source. The original product documentation gives two independent UPS systems as an example of the input power sources.
The system incorporates an Intelligent Power Fail Detector (IPFD) for rapid power source sensing, together with SCR switching and break-before-make transfer operation. This switching arrangement prevents cross-connection between the two AC input sources.
Four models are documented: STS-332, STS-340, STS-363 and STS-3100. The series also provides manual transfer triggering, selectable preferred input, bypass capability and a removable electronics module.
AVAILABLE MODELS
STS Series Model Ratings
Four current ratings are listed in the original specification. Each model carries a published voltage rating of 480VAC.
STS-332 32A 480VAC Rating
STS-340 40A 480VAC Rating
STS-363 63A 480VAC Rating
STS-3100 100A 480VAC Rating
SYSTEM FEATURES
Automatic Transfer and System Control
Fast Transfer Operation
Published transfer times are less than 6ms for automatic transfer and less than 0.5ms for manual triggering.
Break-Before-Make Switching
The switching arrangement prevents cross-connection between the preferred and alternate AC power sources.
Removable Electronics Module
A hot-swappable electronics module incorporates automatic transfer and manual triggering facilities. The fixed body includes bypass controls and a keylocked casing.
TECHNICAL DETAILS
Three-Phase Static Transfer Switch Specifications
The following information is taken from the original STS technical specification sheet.
| Models | STS-332 / STS-340 / STS-363 / STS-3100 |
|---|---|
| Rated Current | 32A / 40A / 63A / 100A |
| Listed Voltage Rating | 480VAC |
| Preferred AC Input | 415VAC ±10%, 3-Phase, 50Hz ±6% |
| Alternate AC Input | 415VAC ±10%, 3-Phase, 50Hz ±6% |
| AC Output | 415VAC, 3-Phase, 50Hz |
| Switching Technology | SCR Ultra-Fast Switching |
| Power Sensing | Intelligent Power Fail Detector (IPFD) |
| Automatic Transfer Time | Less Than 6ms |
| Manual Triggering Time | Less Than 0.5ms |
| Efficiency | Greater Than 99% |
| Crest Factor | 3.5 |
| Power Factor | 0.5–1.0 |
| Number of Poles | Four Breaker Poles |
| Surge Protection | 20 Joules at 10/100µs; 1200A at 8/20µs |
| Monitoring | Digital Voltmeter, Status LEDs and Remote Dry Contacts |
| Ambient Temperature | 45°C Maximum |
| Relative Humidity | Up to 95%, Non-Condensing |
| Dimensions (W × D × H) | 420 × 325 × 430mm |
| Approximate Weight | 23–33kg |
SYSTEM CONSTRUCTION
Fixed Body and Hot-Swappable Electronics
The STS is described as having two main sections for electrical connections, control and transfer operation.
Fixed Body
Contains input and output connections, the bypass control switch, a digital voltmeter and status indicators.
Hot-Swappable Electronics Module
Contains the automatic transfer and manual triggering functions. The original brochure describes module replacement without de-energising the connected load equipment.
ORIGINAL TECHNICAL DOCUMENTATION
STS Series Technical Specification and Diagram
The original manufacturer's specification image contains the technical details and schematic information for the three-phase static transfer switch.
PRODUCT HIGHLIGHTS
What You Get
Four STS models with current ratings from 32A to 100A.
Automatic transfer between preferred and alternate AC power sources.
IPFD power sensing with fast SCR switching and break-before-make operation.
Manual transfer, bypass capability, status indication and a hot-swappable electronics module.
STATIC TRANSFER SWITCH ENQUIRY
Enquire About the STS Series
Provide your three-phase power requirements, preferred and alternate AC source details and required current rating to enquire about a suitable STS model.
Inquiry - STS Series 3-Phase Static Transfer Switch (32A–100A)
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Static Transfer Switch
