SSRL240-660

Supported Applications

The Omega SSRL240/SSRL660 series are single-pole, normally open solid-state relays (SSRs) designed to control large resistance heaters in conjunction with temperature controllers. These devices utilize a zero voltage switching design that switches at the 0-voltage crossover point of the AC cycle to minimize electrical noise (RFI). The SSRs feature an SCR-based architecture capable of tens of millions of cycles and are used for controlling resistive loads up to 40 kW.

Configurations support single-phase control or three-phase load management:

• Three-Phase Y-Loads (with neutral): Use 3 SSRs.
• Three-Phase Delta Loads (no neutral): Control using 2 SSRs.
• Redundant Three-Phase Systems: Use 3 SSRs when there is no neutral load to provide redundancy and extra assurance of control.

Note: These products are not designed for use in, or should not be used for, patient-connected applications. Installation and servicing require qualified technicians familiar with high voltage and current circuits.

Operating Conditions & Performance

The series operates within an ambient temperature range of -20 to 80°C (-5 to 175°F) and a storage temperature range of -40 to 80°C (-40 to 175°F). Electrical isolation is rated at 4000 Vrms from input to output, with 2500 Vrms between the input/output and ground. The line frequency range covers 47 to 63 Hz.

Performance specifications vary by model voltage class:

• SSRL240 Series (AC or DC Control): Nominal AC Line Voltage of 24 to 280 Vac. Maximum contact voltage drop is 1.6V.
• SSRL660 Series (AC or DC Control): Nominal AC Line Voltage of 48 to 660 Vac. Maximum contact voltage drop is 1.6V.

Response times are documented as:

• Turn-On Time: 20 ms (AC); 05 cycle (DC).
• Turn-Off Time: 30 ms (AC); 05 cycle (DC).

The normal failure condition for these SSRs is 'closed' contacts. A small leakage current exists when the contacts are in the open state, with values specified at 25°C max ambient: SSRL240 models show 0.1 mA at 120 Vac and 240 Vac; SSRL660 models show 0.25 mA across 120 Vac, 240 Vac, and up to 660 Vac.

Configuration Options

The series offers configurable control inputs (AC or DC) and load current ratings from 10 A to 100 A. Models are identified by the format SSRL<Voltage><Control Type><Current>, such as SSRL240DC50.

Electrical Connections:

• Screw terminals labeled 1/L1, 2/T1, 4/A2, +3/A1.
• LED input status indicator included on units.

Fuse Protection and Accessories

A special Fast Blowing I²T fuse is recommended in the load circuit. The series supports various KAX-series fuses (KAX-10, KAX-25, KAX-30, KAX-50, KAX-70) and KBH models (KBH-50, KBH-70). Compatible fuse blocks include FB-1, FB-2, FB-3 for lower current fuses, and BS-101 for higher capacity units.

Thermal Management:

• Finned Heat Sinks (FHS) are required: FHS-1 (2°C/W), FHS-2 (1.2°C/W), or FHS-6 (0.7°C/W).
• The SSRs must be mounted on a finned heat sink or metal plate of adequate size to dissipate heat, as the current-switching rating decreases with temperature.

Additional Options:

• DIN Rail Adaptor (SSRL-DINRAIL-ADAPT) for 10 A models only.
• Shunt Resistors: SSRR20-12, SSRR20-50, SSRR15-12, and SSRR15-50 are available for controllers with AC SSR (Triac) output. Note that 12 W versions are specified for 120 V circuits and 50 W for 240 V.

Key Product Differences

The series is divided into two primary voltage classes based on the nominal AC line voltage:

• SSRL240 Models: Designed for lines up to 280 Vac. Available with AC control signals (90 to 280 Vac) or DC control signals (3 to 32 Vdc). Current ratings include 10 A, 25 A, 50 A, 75 A, and 100 A.
• SSRL660 Models: Designed for lines up to 660 Vac. Available with AC control signals (90 to 280 Vac) or DC control signals (4 to 32 Vdc). Current ratings include 50 A, 75 A, and 100 A.

Control signal turn-on thresholds differ by type: AC models require 90 Vac; DC models for SSRL240 require 3 Vdc (turn-off at 1 Vdc), while SSRL660 DC models require 4 Vdc (turn-off at 1 Vdc). Maximum input current is 10 mA for AC control and 14 mA for DC control. Output peak voltage ratings are 800V for SSRL240 series and 1200V for SSRL660 series.