Basics of Solid State Relays for Industry

Solid State Relays from Sords Electric

What are they and how they work in industry.

A Solid State Relay (SSR) is an electronic power switch that is controlled by a separate control input.

With no control signal to the control inputs, the output switch will be open and the output circuit will be off.  Therefore NO power will flow to the load.

When the proper control signal is applied the the control inputs, the output switch closes, completing the output circuit.  Power will FLOW to the load.

This type of control of an SSR is known as On-Off control and is similar to how a mechanical relay operates.  For example;  Mercury relays and electro-mechanical relays (contactors).

However, Solid State Relays have several advantages over mechanical relays (contactors).
These advantages include: No moving parts, no audible noise, longer life, No arcing, higher switching speeds, and shock & vibration resistance.

On-Off Solid State Relays (SSRs) come in two types, Zero Switching (Zero Cross) and Instant On.

ZERO Switching SSRs switch ON at the first zero crossing point of the AC sine wave after the application of the control voltage. And conversely the SSR switches off at the first zero crossing after control power is removed.

Random switching of instant ON SSRs switch ON instantly with the control voltage is applied to the circuit no matter the place on the sine wave where is voltage is.

Another type of switching is Peak switching where the SSR (Solid State Relay) turn on at the first PEAK of the sine wave.  Peak switching is mostly used for inductive loads and transformers.

Solid State Relays (SSR) can be used for DC switching as well. When voltage is applied the DC SSR switches on at the same instant as when the control voltage is applied to the SSR input. DC SSRs are used with resistive loads for the control of DC motors and valves.

ANALOG switching Solid State Relays are used where very tight control is needed in a process. These SSRs require an analog signal for switching. The most common signals are 4 to 20mA, 0-10 vdc, 0-5 vdc and 1-5 vdc. These SSRs are called phase angle solid stat relays and are commonly used in resistive or slightly inductive loads including lighting and HVAC loads. Soft start can be utilized with analog switching SSRs.

Another similar SSR firing method to analog switching is burst or distributed switching. This kind of switching can be used with a PID controller providing the control signal to the SSR.  A number of full cycles are switched on over a predetermined amount of time. Bust or distributed firing limits the limits the seen voltage over time to better control the load and even it out.

There are some limitations for SSRs.

SSRs generate heat so precautions must be made to keep the SSRs from over heating and failing with the use of Heat Sinks. Please review the heat sink charts for the Solid State Relay you plan to use to get the correct amount of cooling required. Some heat sinks can come with a fan. Also some SSRs come complete with a integral heat sink for plug and play application.

Fuses should be used for over current protection on SSRs.
A semiconductor fuse is best for the SSR protection. This type of fuse provides Type 2 protection coordination and has the smallest let-through (I²t) value. Due to UL 508 requirements, fast acting Class CC or J fuses are the most types used for SSRs.  These fuses only provide Type 1 protection coordination and have a high let-through (I²t) value. Circuit breakers are typically not suitable protection for Solid State Relays because f their relatively slow reaction speed.

Industrial control panels are covered by the requirements in the Standard for Industrial Control Panels, UL 508A.

Sords Electric
216-765-4230
www.sordselectric.com

Solid State Relays...Solid State Relays...Solid State Relays...Solid State Relays...Solid State Relays

Three Phase Monitors from Carlo Gavazzi

3 Phase monitoring Relays from Gavazzi and Sords Electric

Get Quote from Sords Electric HERE!

Part Numbers are:

DPB01CM44  DIN Rail mounting
PPB01CM44   Plug In

DPB01CM44 and PPB01CM44 relays are three phase mains monitoring devices.
They can operate on both 3Ph and 3Ph+N mains detecting, besides the phase loss and the correct phase sequence, possible overvoltages and undervoltages.
Power supply is provided by the monitored mains, is wide input range and switch mode. Consumption, dissipation and consequently heat are very limited.
A delay on alarm, up to 30s, for the over/under voltage alarms, filters unwanted trippings for temporary conditions.
Operating frequency is up to 400Hz. 

DPB02CM44  DIN Rail mounting
PPB02CM44   Plug In

DPB02CM44 and PPB02CM44 relays are threephase mains monitoring devices.
They can operate on both 3Ph and 3Ph+N mains detecting, besides the phase loss and the correct phase sequence, possible phase values asymmetries.
Power supply is provided by the monitored mains, is wide input range and switch mode. Consumption, dissipation and consequently heat are very limited.
A delay on alarm, up to 30s, for asymmetry alarm, filters unwanted trippings for temporary conditions. Operating frequency is up to 400Hz. 

DPC01DM44  DIN Rail

DPC01DM44 relay is a multifunction threephase mains monitoring device.
It can operate on both 3Ph and 3Ph+N mains detecting, besides the phase loss and the correct phase sequence, possible overvoltages and undervoltages or asymmetry and tolerance excess.
Power supply is provided by the monitored mains, is wide input range and switch mode. Consumption, dissipation and consequently heat are very limited.
It is certified for Marine applications and it operates up to 400Hz of mains frequency. 

DPC02DM44  DIN Rail
DPC02DM44 relay is a multifunction threephase mains monitoring device.
Power supply is provided by the monitored mains, is wide input range and switch mode. Consumption, dissipation and consequently heat are very limited 

October 30, 2019 - Buffalo Grove, IL – CARLO GAVAZZI is proud to announce the launch of several new Three-Phase Monitoring Relays which feature a Wider Input Voltage Range. These new models, part of the DPB and DPC families, are ideal for distributors and customers as they reduce the number of individual items that need to be stocked, while providing unsurpassed quality and functionality.
The new DPB and DPC models feature an upgraded switch mode power supply, which provides a wider input voltage range to cover different mains voltages, while reducing heat dissipation and improving reliability and stability. The DPB series has an input voltage range of 208 VAC to 480 VAC, while the DPC series has an input voltage range of 208 VAC to 690 VAC. All of the new models feature an expansive frequency range of 50 Hz to 400 Hz, making them ideal for a wide range of applications.
Three phase monitoring relays are ideal for protecting motors from severe damage that can result from loss of a phase, phase imbalance, or phase reversal. Motors can be found in a wide range of applications, including: HVAC systems, water treatment, material handling, machine tool, marine and aviation.
Key features of the DPB and DPC Three Phase Monitoring Relays include:

 

•   Noise, harmonics, and transient filtering
  
•   Significant reduction in power consumption
  versus previous models
  
•   Wide input voltage and frequency range
  

 Voltage ranges selectable by DIP switches  DIN Rail mounting
 Plug-in option available for DPB series 

Get Quote from Sords Electric HERE!

Sords Electric
216-765-4230
www.sordselectric.com

Carlo Gavazzi 3-Phase voltage Monitoring Relay ~~~ Carlo Gavazzi 3-Phase voltage Monitoring Relay

Watlow Mineral Insulated Strip Heaters

MI - Mineral Insulated Strip Heaters from Watlow

Get a Quote HERE! from Sords Electric

The MI strip heater is a thin, responsive heater that uses the most advanced heater construction techniques. A nickel-chromium element wire is embedded in Watlow’s exclusive mineral insulation material, which has a much higher thermal conductivity than the mica and hard ceramic insulators used in conventional heaters. This thin layer of insulation brings the element wire closer to the heater sheath. The result is heat flows easily from the element wire to the sheath allowing the wire to run cooler than conventional heaters and increasing heater life.

Higher watt densities than any other strip heater for faster heat-up

Exclusive mineral insulation combines dielectric strength and superior thermal conductivity

304 stainless steel sheath maintains the high compaction of mineral insulation

UL® component recognition for most 240VAC or less designs

480VAC maximum voltage

Rapid ship Part Numbers are:

MS1J8AS3 - 240 VOLT 500 WATT
MS1J12AV2 - 120 VOLT 350 WATT
MS1J12AV3 - 240 VOLT 350 WATT
MS1J12AS2 - 240 VOLT 800 WATT
MS1J18AS1 - 120 VOLT 1000 WATT
MS1J18AS2 - 240 VOLT 1000 WATT

Get a Quote HERE! 

Sords Electric
216-765-4230
www.sordselectric.com

WATLOW MINERAL INSUlATED STRIP HEATERS ... WATLOW MINERAL INSUlATED STRIP HEATERS

Watlow Mineral Insulated Band Heaters

Sords Electric Sells Barrel and Band Heaters from Watlow

Mineral Insulated (MI) Band/Barrel Heaters

The MI band heater from Watlow® is a high-performance heater. The band heater's performance and name are derived from Watlow's exclusive mineral insulation—a material with much higher thermal conductivity than mica and hard ceramic insulators used in conventional heaters. A thin layer of the “high” thermally conductive MI material is used to electrically insulate the element wire from the inside diameter of the heater sheath. A thicker, “low” thermally conductive layer backs up the element wire directing the heat inward toward the part being heated. 

High thermal conductivity of MI and low mass construction provides rapid response to temperature control and avoids thermal lag.

Operating temperatures up to 1400°F (760°C) allows safe melting of resins such as PEEK™, Teflon®, Ultem® and Zytel®

Higher watt densities contribute to faster heat-up and throughput for increased productivity

Stainless steel cover and side fold design resists contamination from overflow of plastic or other free-flowing materials

Attached clamp bars eliminates cumbersome clamping straps, making installation easier

Applications and Technical Data 

General Limitations 

• Maximum width of 1 in. (25 mm) diameter heater is 11/2 in. wide (38 mm) 

• Maximum heater width: 2x heater diameter 

• Minimum I.D. for Type B, C, E and H leads: 1 in. (25 mm) 

• Minimum I.D. for Type B—90° leads: 11/8 in. (29 mm) 

• Maximum lead amperes: 12.5A per pair 

• SLE maximum: 17.0A 

• Maximum amperes (post terminals): 30A per pair 

• Minimum diameter and width for SLE: 4 in. x 11/2 in. (102 x 38 mm) width 

• 90° leads not available over 250VAC 

• Minimum I.D. for post terminals: 11/4 in. (32 mm) 

Gaps 

• ≤ 3 in. = 1/8 in. nominal 

• 3 in. ≤ 6 in. = 1/4 in. nominal ±1/8 in. 

• 6 in. ≤14 in. = 3/8 in. nominal ±1/8 in. 

• >14 in. = 1/2 in. nominal ±1/4 in. 

Use our Contact Form HERE to get a quote on Watlow Band /BarrelHeaters

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Use our Contact Form HERE to get a quote on Watlow Band /Barrel Heaters

Sords Electric
216-765-4230
www.sordselectric.com

Band Heaters and Barrel Heaters from Watlow 

Watlow Nozzle Heaters

Sords Electric Sells Watlow Mineral Insulated Nozzle Heaters

Use our Contact Form HERE to get a quote on Watlow Nozzle Heaters

Mineral Insulated Nozzle Heaters

The MI nozzle heater from Watlow is a high-performance heater. The nozzle heater's performance and name are derived from Watlow's exclusive mineral insulation—a material with a much higher thermal conductivity than mica and hard ceramic insulators used in conventional heaters.

A thin layer of the “high” thermal conductive MI material is used to electrically insulate the element wire from the inside diameter of the heater sheath. A thicker, “low” thermal conductivity layer backs up the element wire, directing the heat inward toward the heated part. The result is more efficient heat transfer—a performance solution lowering element wire temperatures and increasing heater life.

Performance Capabilities

• Heater operating temperatures up to 1400°F (760°C)

• Watt densities up to 230 W/in2 (35.6 W/cm2) are

   available on small diameter nozzle

• Maximum voltage up to 240V

Operating temperatures to 1400°F (760°C) safely melts resins such as PEEK®, Teflon®, Ultem® and Zytel®

Higher watt densities contribute to faster heat-up and throughput for increased productivity

High thermal conductivity of MI and low mass construction provides an almost instant response to temperature control

Stainless steel cover and side fold design resists contamination by overflow of plastic or other free-flowing materials

Permanently attached clamp bars eliminate cumbersome clamping straps for easier installation

Typical Applications

• Extruders

• Blown film dies

• Injection molding machines

• Other cylinder heating applications

Watlow nozzle Heater Part Numbers.

MB1A1AN1

MB1A1AN2

MB1A1AN3

MB1A1AN4

MB1A1JN1

MB1A1JN2

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MB2E2AX7

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Use our Contact Form HERE to get a quote on Watlow Nozzle Heaters

Sords Electric
216-765-4230
www.sordselectric.com

Watlow Nozzle Heaters for Industrial Uses

Robertshaw Vibration Switches - Uniline Switches

2020
Schneider Electric Uni-Line Robertshaw Vibration Switches from Sords Electric

Buy Here!

The Robertshaw vibration switch is designed to protect rotating and reciprocating equipment against serious damage in the event malfunctions occur which maybe detected as an increase in vibration.  Both amplitude and frequency of vibrations as so that an increase over normal in either will actuate the vibration switch.  When the vibration level of a machine protected by a vibration switch exceeds normal by a preselected amount, an internal switch is actuated providing a shut down circuit before costly damage occurs.  An audible or visual warning system may also be wired into the switch to signal when the malfunction has occurred. Falling bearings, broken blades and similar malfunctions cause increased imbalance or high frequency vibrations, detachable with the Robertshaw vibration switch. The Robertshaw vibrations switch is designed for maintenance free service in permanent locations.

Two types of the vibration switch are available. The Robertshaw/Uniline 366 and 365/365A series.

The 366/6000-00 series are enclosed in a general purpose housing which meets weather resistant NEMA 4 specifications.
The Uni-Line/Robertshaw 365A/6000-10 vibrations switch conforms to specifications for use in hazardous locations with a NEMA 7 housing the meets Class 1, Groups C and D and Class 2, Groups E, F and G hazardous area classifications.

The difference in the switch part numbers are the RESET coil voltage and either SPDT OR DPDT switches. Note: All switches can be manually reset after a fault.

366 series switches - NEMA 4

366-A2  or  Uni-line P/N 6000-002 - SPDT, 24 vdc reset
366-A4  or  Uni-line P/N 6000-004 - SPDT, 48 vdc reset
366-A8  or  Uni-line P/N 6000-005 - SPDT, 117 AC/VDC reset

366-D2  or  Uni-line P/N 6000-007 - DPDT, 24 vdc reset
366-D4  or  Uni-line P/N 6000-008 - DPDT, 48 vdc reset
366-D8  or  Uni-line P/N 6000-009 - DPDT, 117 AC/VDC reset

Buy Here!

365A series switches - Hazardous rated Explosion Proof Housing

365A-A2  or  Uniline P/N 6000-102 - SPDT, 24 vdc reset
365A-A4  or  Uniline P/N 6000-104 - SPDT, 48 vdc reset
365A-A8  or  Uniline P/N 6000-105 - SPDT, 117 AC/VDC reset

365A-D2  or  Uniline P/N 6000-107 - DPDT, 24 vdc reset
365A-D4  or  Uniline P/N 6000-108 - DPDT, 48 vdc reset
365A-D8  or  Uniline P/N 6000-109 - DPDT, 117 AC/VDC reset

Buy Here!

NOTE: The Robertshaw 365 series Vibration switch is now the Robertshaw 365A series Vibration switch with updated internals.
It has the same Form, Fit and Function.

To get a quote, please use our CONTACT US page.

Range - 0 to 4.5G
Accuracy -  ~5% of full range up to 300 Hz
Contact Rating -
  7 amp max., 460V AC Max., 50/60 Hz resistive load
  .5 Amp Max. 120VDC Max. resistive load
  1 Amp Max. 48VDC Max. resistive load
  2 Amp Max. 24VDC Max. resistive load
  5 Amp Max. 12VDC Max. resistive load
  5 amp max., 240V AC Max., 50/60 Hz resistive load DPDT
Temperature Limits -= -40ºF - 200ºF
Weight is 2.5 pounds for NEMA 4 and 6 pounds for Explosion-Proof housing units

Buy Here!

Sords Electric
Cleveland Ohio
216-765-4230
www.sordselectric.com

Schneider Electric Robertshaw Uni-Line Vibration Switches

Capacitive Proximity Sensors with Relay Output

Sords Electric Sells Carlo Gavazzi Capacitive Proximity Switches

CARLO GAVAZZI  Multi-voltage CA30CLN12M Series Capacitive Sensor with Relay and Optional Time Delay Output available from Sords Electic. These sensors provide reliable detection of solid, fluid or granulated substances and are equipped with a two amp SPDT relay output, with a time delay of up to ten minutes. This self-contained solution assures a robust output and sensing flexibility.

The Carlo Gavazzi  CA30CLN12M Series is constructed in a threaded M30 housing, for simplified mounting ease. The back of the sensor features up to two IP67 integrated adjustment potentiometers for adjusting the sensing distance and an optional potentiometer for the time delay. The adjustable time delays available include: On-Delay or Off-Delay.

This sensor series is specifically designed for feeding systems and silo applications in the agricultural market, but can be used in most industrial applications. 

Technical specifications include

	Multi voltage power supply 21 to 255 VAC/DC
	2 A SPDT relay output
	M30 PBT housing with cable connection
	Up to two integrated IP67 rated trimmer potentiometers
	Multi-turn potentiometer for distance: 4-12 mm
	Optional multi-turn potentiometer for time delay: 1 second to 10 minutes
	Laser printing of the main specifications on the sensor
	IP67 ratings and NEMA 1, 2, 4, 4X, 5, 6, 6P and 12
	cULus approval as well as CE marking CA30CLN12MU10M On-Delay,  Time Delay, 24-230 AC/DC CA30CLN12MV10M  Off-Delay,  Time Delay, 24-230 AC/DC CA30CLN12MT No Time Delay  Please use our Carlo Gavazzi Parts form for a quote, HERE!

Sords Electric
216-765-4230
www.sordselectric.com

Carlo Gavazzi Compact 3-Phase Monitors

Sords Electric Phase Protection from Carlo Gavazzi

To get a quote with our Carlo Gavazzi Parts Form, click HERE!

The Carlo Gavazzi  DPA52 and DPB52 provide critical protection against phase loss and improper phase sequence, with DPB52 adding additional protection against under-voltage and over-voltage.

Gavazzi DPA52 and DPB52 Phase Monitors

Optimizing panel space is a primary goal for most manufacturers. Thanks to the low profile DIN housing and 17.5mm width, it is possible to install these monitoring relays in industrial cabinets as well as in electrical distribution NORM panels. With a built-in switch mode power supply, DPA52 and DPB52 have the added advantage of filtering and minimizing harmonic distortions, which can help prevent devices from overheating and most of all prevent failures and false alarms which could lead to unexpected machine downtime.
The DPA52 and DPB52 come with features that offer versatility and ease of use, including wide input voltage range, multi-color LED indicators for visual status, and a relay contact output. They conform to global standards such as UL 508, CSA C22.2 and EN 60947-5-1, and can be used globally in applications/markets where it is necessary to monitor phase presence, sequence, and value, such as HVAC, Lifts and Escalators, Material Handling, Water Treatment, and others.

The features of the DPA and DPB Compact 3-Phase Monitors include: 

 Screw terminals

 Alarm LED with type of alarm indication
 Switch mode power supply
125VLL to 624VLL (208V -40% to 480V +30%)
Operating frequency from 45 to 65Hz 
17.5mm wide - DIN rail mounting 

The DPB52 has an adjustable voltage range while the DPA52 does not.

Sords Electric
216-765-4230
www.sordselectric.com

ATC SLM Voltage Monitor

Sords Electric sells the ATC SLM series 3 Phase Voltage Monitor

The SLM Series Microprocessor-based Three-Phase Monitor from the ATC Diversified Electronics division of Marsh Bellofram Corporation is a microprocessor based 3 phase monitor. This device protects 3 phase equipment from under voltage, over voltage, phase loss, phase reversal, phase unbalance, phase shift and frequency shift. Models available up to 690 vac and comes complete with automatic or manual reset, delay-on-make timer, LED indicators for fault conditions and last fault memory.

ATC Diversified Voltage Monitor SLM

Features

Models available to 690 VAC

Automatic or Manual Reset

Delay-On-Make Timer

LED Indicators for Fault Conditions

Last Fault Memory

Screw Driver Adjustment for Time Delay, 

Voltage and Mode of Operation

The ATC Diversified voltage monitor 

SLM series protects against :

Under Voltage

Over Voltage

Phase Loss

Phase Reversal

Phase Unbalance

Phase Shift

Frequency Shift

Part Numbers are :

SLM-120-ASE (Max Voltage is 143)
SLM-230-ASE (Max Voltage is 275)
SLM-380-ASE (Max Voltage is 457)
SLM-440-ASE (Max Voltage is 540)
SLM-575-ASE (Max Voltage is 690)


Sords Electric
216-765-4230
www.sordselectric.com

Selecting Solid State Relays

Sords Electric Sells SSRs or Solid State Relays
Selecting the right relay is important for long life and application efficiency.

BUY SSRs HERE!

Here is guide to selecting and installing (SSRs) Solid State Relays.

A solid state relay or SSR is an electronic device that switches loads on or off when an external voltage or signal is applied to its control terminals. The lack of moving parts in an SSR allows it to switch much faster that electromechanical relays while avoiding the creation for electrical arcs. Solid Sate Relays are also silent, so users won't be subjected to the annoying noise associated with electromechanical relays. Furthermore, because SSRs have no moving parts or contacts that can wear out, SSRs last longer and require less maintenance than electromechanical relays.

SSRs are used in a variety of applications where quick, silent switching is advantageous. Some of these industries include: plastics/rubber, Food and beverage, processing, packaging, HVAC, semiconductor, oil/gas, transportation, conveyors, power or energy systems, printing, laboratory,kiln/oven, lighting, medical/pharmaceutical, and motion control.

How will your solid state relays be mounted/installed?

SSRs are available in a few mooting configurations. Printed circuit board (PCB) mont SSRs are limited in load size due to electric creepage and clearance distance and heat dissipation constraints.
Chassis munt SSRs are often installed to a back panel of an electrical panel but may also mount directly to a metal surface within a machine or appliance. Typically, the SSR can be mounted without a heat sink if the load is un 5 amps or under 8 amps if the mounting surface is an unpainted metal plate. To achieve the desired maximum SSR output rating, a sink sink must be properly sized and installed along with the SSR.

Engineers wo tont want to worry about properly sizing and mooting a heat sink can opt for an SSR with an integrated heat sink. These typically snap directly onto the DIN rail and are ready to wire up and use. Many of the more advanced Ssts, such as those enabling proportional control, are available in this design.  Is it also easier to obtain agency approval with SSRs integrated heat sinks, which are typically cUL listed and carry horse power ratings.

How Many Poles Need to be Switched?

When selecting a Solid State Relay, you will need to know how many polkas  (or lines of voyage) are to be switched to the load.  If your application uses a DC load, you'll need a one pole DC switching SSR. For a single-phase AC load you'll need a one pole AC switching SSR.  For a three phase AC load, you'll need to determine if you want to switch all three poles to the load or if you can get by with only switching 2 poles.  This can be achieved with a two-pole or three-pole three phase switching SSR.

What is Your Load Voltage and Current?

You will need to determine the maximum AC or DC voltage and current for your load. These variables are typically found on the specification of your motor, heater or other electrical device. For AC loads, SSRs usually switch on phase at 120 or 240 VAC or for three phase applications: 208, 240, 480 or 600 VAC.  Also factor in any potential power sags or surges in the application location when determining the minimum and maximum load voltage. DC loads are gong to be powered by DC voltage.
For motors, you will need to know the maximum horse power or kilowatt rainy at the respective voltage of your application. Check for these specs on the motor name plate.

What is the control voltage or input signal to turn the SSR on?

Next you'll need to determine another kind of voltage, the pick-up voltage that is required to energize your load as its turn off voltage (at which your load will de-energize). These are the critical control voltages for your SSR, and are usually found on your loads spec sheet. Unlike electromechanical relays or contractors which typically are controlled by a fixed voltage, SSrs have input ranges either VDC or dual VAC/VDC.
If you wish to proportionally control your load, you'll need some additional specs to choose the proper SSR. Proportional control is typically done with a 0-5, 1-5 or 0-10 VDC input or a 4-20mA control signal. Be sure to consult with a SSR manufacturer to determine the optimum out-put switching type for your load application, as it can get a bit sophisticated. Proportional output types include phase angle, distributed full cycle, burst full cycle, soft start and burst full cycle with soft start.

What is the Ambient temperature where the SSR will be installed or located?

The maximum SSR current rating depends upon the ambient temperature where is will be used and installed. Heightened temperatures can reduce the SSRs current rating.  Any SSRs are mounted on a chassis and require a heat sink t ptomaine their performance. you will need to know the ambient temperature, as well as the mounting orientation upfront, to properly ensure the right type of heat sink is specified.  Highly competent SSR manufacturers provide online tools to help match single or multiple SSRs with the appropriate heat sink. With Din rail mountable SSRs the heat sink is already integrated and the ratings are typically listed on the side of the device or data sheet for various ambient temperatures.  Keep in mind that higher ambient temperatures will require you to de-rate the current rating of the Solid State Relay.


BUY SSRs HERE!



Sords Electric
216-765-4230