2N2646 based Voltage controlled SCR Pulser

 Mains-Power, Power-Supplies  No Responses »
Oct 152008
 

A Center tap 50Hz Step Down Transformer with two diodes is used to get a train of Positive Sine Pulses at 100Hz which is applied to Q6 base via R51. 2N2646 is a unijunction transistor(UJT) in a TO-18 metal package. The control voltage or voltage proportional to error is fed to R56-Q3, The UJT drives a pulse transformer which provides isolation from the Load which the SCR bridge is controlling. This phase angle control gives a near Linear closed loop control for a SCR bridge which may be used in Electroplating or a Preregulator of a big power supply.

2N2646 based Voltage controlled SCR Pulser

 Posted by admin at 3:30 AM  Tagged with:

AC-AC-SSR Solid State Relay

 Mains-Power, Solid-State-Relay  No Responses »
Jul 032008
 
AC-AC-SSR Solid State Relay

This is a AC Control Input AC Output SSR Solid State Relay. When a Process Controller has an AC output or a system generates an AC signal of above 100V AC to signal the load to turn on, this device can be used. A BTA40-600 and MOC3041 are used in this. A high voltage plastic cap limits current to a bridge which generates a small DC from 230 V AC, this drives MOC3041. The rest is the same. It is better to use a DC control SSR where possible. This AC control SSR is used where only an AC control Read More …

 Posted by admin at 6:55 AM  Tagged with:

Normally Closed AC SSR

 Mains-Power, Solid-State-Relay  No Responses »
Jul 032008
 
Normally Closed AC SSR

This is a Normally Closed PCB Mount SSR. That means when DC Control input is low, the triac is ON, the output passes the load current to turn on small heater-motor-lamp or a bigger contacter-drive etc. When input DC is high the output is OFF. This is also Optically Isolated from Mains. A Microcontroller output which is buffered by some driver can drive this relay. It is better that in big systems these SSR Modules can be on another PCB, to avoid mains wiring near Logic circuits. But this cannot be used for medical electronics, or critical applications. More reliability Read More …

 Posted by admin at 3:38 AM  Tagged with:

NO-NC SSR Plastic Box

 Solid-State-Relay  No Responses »
Jun 012008
 
NO-NC SSR Plastic Box

This was a Fire Retardant Plastic Box which was made for the SSR I/O Stackable Modules. DC Control for an AC Load. Usually it is to control another Big Three phase contactor; Pneumatic or Steam Valve, Solenoids-Motors. When Mounted at the end of the PCB it offers over 2kV Isolation from the Digital Circuits. The Output 230V signals NO-NC, can control Light Loads like the Coil of a Big 230V Relay also called contactor. It could be Mounted on a PCB by soldering or a Plugin Base. It is better to have Crimped connections or Terminals. A very good quality Read More …

 Posted by admin at 7:56 AM  Tagged with:

Three Phase Solid State Relay

 Solid-State-Relay  No Responses »
Apr 062008
 
Three Phase Solid State Relay

This is R-Y-B three phase 40A 440V AC Solid State Relay with 3-30 V DC Control Signal. It has Built in HeatSink and Fan. It is good for Controlling a Bank of heaters. This model could go upto 120A with SSR’s in parallel for Proportional Control. Solid State Relays SSR. This is a Contacter replacement, it will switch R-Y-B phases. It is a high power SSR. In some places it is unwise to use an SSR, a Electromechanical Contacter will perform better. The merit of SSR is fast switching, no wear and tear. No dust humidity influence. This post was Read More …

 Posted by admin at 9:33 AM  Tagged with:

Solid State Relay – Common

 Mains-Power, Solid-State-Relay  No Responses »
Oct 282004
 
Solid State Relay - Common

This is a DC controlled Solid State Relay which can turn 230V AC equipment on and off. The output is like a NO normally open contacts of a relay and have to be in series with the Load like any other switch. This should not be used for large inductive loads like big motors. The Q1 transistor limits the current thru the LED by providing an alternate path for more current. The DC input can be from 3V to 20V. The Triac can be chosen depending on current in the load. Look for datasheets and applications at STMicroelectronics for BTA41600 Read More …

 Posted by admin at 7:38 PM  Tagged with:

Triac based Lamp Dimmer power control

 Mains-Power  1 Response »
Oct 262004
 
Triac based Lamp Dimmer power control

This is a phase angle control of a Triac which is a evolution from an SCR. The 50 Hz or 60 Hz Sine wave of mains can be turned on at any point after the Zero Crossing The Voltage ramps up in the sine wave which gives a near “Linear” slope which can be used to trigger the ON at a time delay after zero crossing when the voltage is zero. This is like a PWM but works on low frequency only. Some of the early SMPS(HV for TV and Mains Inverter) by Siemens were built around SCRs. Turning off Read More …

 Posted by admin at 8:34 AM  Tagged with:
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