WUI Spec - S4H/S4L

The Model S4 Transfer Switch is a multiple channel passive A/B switching instrument. It is designed for airport runway lighting control application. The S4 can switch the multiple lighting control relay current as required by the FAA fiber optic communications system. It can also be used for general purpose multi-line A/B switching applications. There are two variations available in the Model S4 series: S4H and S4L. Both share a common set of features with the exception of the channel (relay contact) current carrying capacity.

The S4 consists of 16 high quality, low contact resistance double pole double throw, two coil latching switching elements (relays). They are organized in two groups of 8 switching elements each. Each group has an independent SET and RESET (or A and B) control. These switching elements provide switching for a total of 32 channels for each S4 unit. The S4 features an individual read back circuit and individual switching state indicator (bicolor LED) for each switching group. All wiring connections are accessed from the top panel via standard D-sub miniature connectors.

The wall mounted S4 Transfer Switch is a passive multiple channel switching system for both signal and current applications. It requires external power only when switching groups are being momentarily driven to initiate a state change. The switched state is magnetically latched.

Model S4H and S4L Transfer Switch Summary Specifications:

Switching Elements:	16 DPDT two coil latching relays
No. of Switching Channels:	32 total, in groups of 16 and 16
Relay Contact Ratings:	Model S4H	Model S4L
Switching Rating/Channel: UL/CSA rating:	1/20 HP, 125/250VAC, 3 A/3A, 250VAC/30VDC	0.6A/0.6A, 125VAC/110VDC, 2 A, 30 VDC
Switching Power/Channel:	1250 VA Max. (Resistive)	125 VA Max. (Resistive)
External Control Power:	260 mA per group at 24 VDC during switching only	70 mA per group at 24 VDC during switching only
Read back Circuits and Indicators:	One per group (two total)
Enclosure:	Wall mount, anodized aluminum sheet metal case
Dimensions and Weight:	12" x 11.25" x 3.5" (H, W, D), Approximately 3.7 pounds