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Showing posts with label Solid-State-Relays. Show all posts
Showing posts with label Solid-State-Relays. Show all posts

Tuesday, November 15, 2016

Three Phase AC SSR for 1 HP Motor

I need to build a three phase AC(in 120V)-AC(out 440V) solid state relay to turn on or off a small(1hp) three phase AC motor. Do you have any idea?

Can I use three MOC3043 and three TIC236E triacs of course with all opto LEDs in series?

Mail from FJP Brazil


See my SSR Circuits , Solid State Relays or SSR Choose a DC Control and AC Load SSR, That is what you seem to indicate.

1 hp = 745.699872 watts

Let triac have 10 A and 600V AC ratings, BTA12600 But now BTA12600 is obsolete, adapt to what is available in your country.

MOC3043 is fine, isolation must be good, take care. Use a Heatsink.
ON-OFF Control inputs can be parallel not series.

Here is a picture of a Solid State Contacter from Power IO

Three Phase AC SSR for 1 HP Motor

On this page you can see a 3 phase SSR i built. Three-Phase-SSR.

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Saturday, June 11, 2016

SSR Open Circuit Leakage Voltage

hi been trying to use a dc ssr relay to switch 24 volt supply on and off for a unit i use that needs to see 0v or 24v but when the switch voltage is applied there is still 18v showing on the load side not zero ..does the ssr have to have a load on it to fully switch off and on from 0v to 24v ?

Mail from PST in UK


You are right you need a bleeder resistor of 10k or 100k to ensure the collector leakage current of SSR is bypassed to make you see a '0' when the SSR is off. If the SSR is working well, and no input or '0' control input then SSR output is high impedance and only a collector or diode leakage will hold the SSR output at the Full Voltage but it cannot drive any current. Hence a bleeder across output will show you a '0'. Use it if the bleeder does not cause any problems.

Solid State Relays or SSR

If you were driving a 5A Solenoid, then you would not see this problem. If you are driving a Solid State Load, such effects are natural. It is because the Solid State Load like a Electronic Circuit will draw current only on demand.

These instruction is for a Normally Open Output, NO. A Normally Closed NC is vice versa. And also some Special SSRs may have sensitive inputs, So a low impedance '0v' at input has to be ensured.

The Bleeder should bypass the leakage current, so one end of bleeder goes to SSR output and other end of bleeder goes to the ground or 0V point of your circuit which is controlled by SSR.

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They are called SSR as there are made of semiconductors and have no moving parts to wear out. They do generate heat depending on load and switching. Thyristors are used in most as they are rugged, mosfets and IGBT may also be used for various applications.

Solid State Relays or SSR

 In this section you will find SSR designs and PCB layouts which you can study. These were made and sold  by me years ago. So the PCB layouts have gone thru some revisions and they worked quite well.

Friday, June 10, 2016

Leakage of SSR driving AC Solenoid

message: I have a 115vac ssr powering a solenoid only pulling a 160ma. upon activation 115vac is applied, but upon deactivation 78vac is still present. I'm told I need a bleeder resistor, but no one knows exactly what size? Can you help?

Mail from GH USA


When a solenoid draws 160mA, you dont need a bleeder. That itself is a bleeder. The leakage of the ssr is very less, it is mainly the current thru the snubber caps.

The SSR cannot leak so much, Is the solenoid a simple coil solenoid or has circuitry? A coil solenoid is also a bleeder for the 1 or 2mA max AC current from caps.

If the solenoid has some control circuit then you may need a bleeder, put a 100K 250V 1W. It also could be a defective SSR or a NC (normally closed) SSR with improper control signal.

Check if control and load circuits are isolated too, make careful measurements across the ssr. Tell me if you still are in doubt.

See the connection diagram

AC-AC SSR Wiring

Connection Diagrams of SSR

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Saturday, April 02, 2016

Sourcing the SP646 Solid State Relay

I have a customer that call out a Solid State relay and i cannot find any information on it. Can you help? It is a SP-646. I need a quote on 60 and 120 pieces.

Mail from PG US


Have a look at this, is this what you want. SP646 1 Form A Solid State Relay. contact them if the specs are right. this is made by Solid State Optronics (SSO)

SP646  bi-directional multipurpose relay

Description

The SP646 is a bi-directional, single-pole, single-throw, normally open multipurpose relay. The circuit is composed of one LED on the input side which activates an optically coupled IC on the output - controlling the firing angle of two back-to-back SCRs. This circuit assures no false triggering under most adverse conditions, and a tight zero-volt window not exceeding 5V.

Features
  • Inverse parallel SCR output
  • High transient immunity
  • 400V blocking voltage
  • 1.2A maximum continuous current
  • Low input control current
  • High input-to-output isolation
  • Solid state reliability
  • Zero-volt switching
Applications

Programmable controls, Valve control, Solenoids, Remote switching, Home appliances, Metering equipment, Heating elements, Gas pump control circuitry,

The SP646 Data Sheet includes the Complete Overview, Electrical Characteristics, and Schematic Diagrams.

Even if you dont find the same number, Digikey or Mouser may have an Equivalent. Just match the Electrical Specs and PCB Footprint, pitch etc.

Components Suppliers - Kits and Parts

Have a Look at my Solid State Relay Pages too

Solid State Relays -  They are called SSR as there are made of semiconductors and have no moving parts to wear out. They do generate heat depending on load and switching. Thyristors are used in most as they are rugged, mosfets and IGBT may also be used for various applications.

DC-DC SSR

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