- The commutating components L and C are used in order to turn off the SCR.
- When the load resistance of very small value is used, the inductor L and capacitor C are connected in series with load.
- Similarly the load resistance of high value is used; the load resistance is connected across capacitor.
Home » Archives for March 2017
31/03/2017
Class A Commutation ( Current or self or Resonance Commutation )
29/03/2017
28/03/2017
27/03/2017
26/03/2017
AC Time Delay Circuit
- The basic circuit for the AC Time delay circuit is shown in the figure A.
- Let us consider that the switch is in the reset position.
- The charging of the capacitor is done through N – (+) C1 – C1 (–) – D2 – R2 – P path during negative half cycle.
24/03/2017
Jones Chopper
- The basic circuit of the Jones chopper is shown in the figure A.
- The Class D commutation circuit is used in the Jones chopper.
- The SCR T1 is main SCR whereas SCR T2, diode D1, capacitor C and auto – transformer T makes commutating circuit for SCR T1.
23/03/2017
21/03/2017
Type E Chopper ( Class E Chopper )
- The type E chopper is a four quadrant chopper.
- The type E chopper is parallel combination of two type C chopper.
- The combination of chopper CH1, chopper CH2, diode D1 and diode D2 makes one type C chopper and other is made from chopper CH3, chopper CH4, diode D3 and diode D4.
20/03/2017
Type D Chopper ( Class D Chopper )
Working
- The two quadrant type B chopper or type D chopper is shown in the figure A.
- This chopper works in first as well as fourth quadrant therefore the output current remain positive but output voltage may be either positive or negative.
19/03/2017
18/03/2017
17/03/2017
Speed Control of DC Series Motor By Chopper
- The speed control of DC series motor by using chopper is shown in the figure A.
- This speed control is achieved through constant frequency control or variable frequency control.
- When chopper CH is switched on, the DC motor gets input supply voltage Vdc.
16/03/2017
Speed Control of Slip Ring Induction Motor By Chopper
- The speed control of the Slip ring induction motor by chopper is shown in the figure A.
- The ON and OFF time of chopper is adjusted in order to get desirable speed of the motor.
- The three phase rectifier converts AC into DC.
15/03/2017
Type A Chopper ( Class A chopper )
- The power circuit diagram of the type A chopper is shown in the figure A. The commutation circuit is not shown in this figure A.
- When chopper CH1 is switched on, the load current flow through path VDC – CH1 – A – L – B – LAOD – C – D – VDC.
14/03/2017
Working of the Step Up / Step Down Chopper
- It is a chopper which can work as step up chopper as well as step down chopper.
- When the chopper is switched ON during TON time, the energy stored in the inductor via path Vdc – CH – L – Vdc.
Working of Step up Chopper
Step up Chopper
- The step up chopper is one in which output DC voltage is greater than the input DC voltage.
- The basic diagram for the step up chopper is shown in the figure A.
12/03/2017
RC Phase Shift Control
- Figure A shows circuit for the RC phase shift control.
- It consists of one step down transformer which consists of center taped secondary winding.
- The RC circuit is connected in series with transformer secondary winding.
RL Phase Shift Control
- Figure A shows circuit for the RL phase shift control.
- It consists of one step down transformer which consists of center taped secondary winding.
Chopper Configuration
The configuration of
chopper is done according to direction of output voltage and output current.
Type A Chopper
Methods of Chopper Output Voltage Control
There are following
methods to control output voltage of the chopper.
Constant frequency control ( Pulse width modulation control )
- The chopping frequency is kept constant in this method therefore it is called as constant frequency control.
11/03/2017
Light Dimmer Circuit OR Fan Regulator Circuit OR AC Load Control Using TRIAC - DIAC
- The fan regulator circuit using TRIAC – DIAC is shown in the figure.
- The TRIAC and DIAC are bi – directional therefore they are used for alternating circuit.
- The RL is load resistance / lamp or two terminal of single phase winding.
Working Principle of DC Chopper
Function of DC Chopper
- The function of the DC chopper is to convert fixed DC into variable DC. A DC chopper is connected between supply source and load.
- The variable output voltage is obtained by switching on and off SCR at regular interval.
Wiring Diagram of Twin Tube Light
Twin Tube light
The
wiring diagram of twin tube light is shown in the Figure. The Twin tube light
is generally used in the textile industry / diamond factory where high level of
illumination required.
Wiring Diagram of Twin Tube light
If you do not know how to connected wiring of twin tube light, it is very easy because this diagram is already shown in the old chokes. Here the ballast indicates choke in the wiring diagram.
10/03/2017
08/03/2017
Control Circuit of Automatic Star Delta Starter
Working of automatic Star Delta starter control circuit
- Press ON push button
- The star contactor coil gets supply through phase R – OFF push button – ON push button – T NC – star contactor coil – D1 ( NC of delta coil ) – phase Y.
Control Circuit of Forward Reverse Starter
Working of Forward – Reverse starter control circuit
Forward direction
- Press ON Push button ( F ON )
- The forward contactor coil gets supply through phase R – OFF push button – R2 – forward contactor coil – ON push button F – phase Y.
Control Circuit of Direct ON Line Starter
Working of Direct on Line Starter Control circuit
- Press ON Push button.
- The main contactor coil gets supply through phase R – OFF push button – ON push button – main coil – phase Y.
Control Circuit of Semi Automatic Star Delta Starter
Working of semi automatic star delta starter control circuit
- Press ON Push button
- The star contactor coil gets supply through phase R – OFF push button – ON push button – star contactor coil – D1 ( NC of delta ) – phase Y.