Download London Model Railroad Group SCR Throttle

SCR UYGULAMA ORNEKLERİ
Dimer devreleri
Silicon Controlled Rectifier Model Railroad Throttles
London Model Railroad Group SCR Throttle
The following is a schematic drawing of a Silicon Controlled Rectifier type throttle for use on larger scale model
railroads. Three versions of this throttle are shown on this page. They are not sophisticated designs but work well and
are tough and reliable.
Push Button SCR Throttle Schematic
It was designed for use on a "The London Model Railroad Group's" large O scale layout located at London, Ontario,
Canada. The prime requirements for the club throttles were that they be rugged, reliable and produce as little heat as
possible. Throttles of this type have been in service at the club since 1987 with excellent results. The throttle will
deliver 5 amps continuously and up to 18 volts DC. See Notes.
The Programmable Unijunction Transistor used to trigger the SCR is the key to this design as it ensures that the
SCR fires on every cycle of the fullwave DC. This gives a very efficient operation with low voltage loss and very little
heat generated. Please refer to your electronics books if you need more information on how the SCR and PUJT in the
circuit function.
The SCR throttle has momentum effect built in due to the memory provided by the 50uF capacitor at the PLUS input
of the OPAMP. There is no decay but this can be added by placing a 1 to 2 Megohm resistor in parallel with the 50uF
capacitor. Increasing the value of the memory capacitor will slow the action of the throttle controls.
Due to its unregulated voltage output, the SCR throttle will have a prototypical feel as trains will slow when climbing
grades and speed up when going down grades. The operator must work the throttle to keep their train from speeding
or slowing too much in hilly terrain.
SCR Throttle Setup Instructions
The 50K Trimmer is adjusted so that maximum output voltage can be obtained but keep the SCR triggering on each
cycle. To do this perform the following steps.
1. With no load connected to the throttle output and the AC input turned on.
2. Connect an analog voltmeter to the output of the throttle (0-30V).
3. Set the trimmer to its maximum resistance.
4. Press and hold the ACCELERATE push button until the output voltage stops increasing.
5. DECREASE the resistance of the trimmer until the output voltage peaks and then begins to fall again. When the
voltmeter needle starts to bounce slightly the SCR is at its maximum trigger angle. STOP.
6. INCREASE the resistance of the trimmer slightly until the meter needle stops bouncing. At this setting the throttle
will be able to deliver its maximum voltage. If the trimmer resistance is set too low the SCR will not trigger on every
cycle of the full wave DC at full output voltage and could be damaged by high current spikes.
Notes
* NOTE 1 At full throttle and with no load this circuit will deliver more than 25 volts. Therefore care must be taken with
auxiliary equipment and train lighting that may be connected to the track.
(Remember that most voltmeters only indicate average or RMS voltage and not the peak voltage which can be 1.4
times greater that the average.)
* NOTE 2 If your trains will run as fast as you need at lower track voltages than 18 volts then lower the input to 12 or
14 volts AC. The under load DC output voltage of this type of throttle is roughly equal to the RMS AC input voltage.
* NOTE 3 Add your own reversing switches to the output and a suitable circuit breaker for added protection if desired.
* NOTE 4 The use of good quality push buttons is a must as these are the most likely components of the throttle to fail
due to the heavy thumbs of some people.
Please feel free to use this design if you wish. It worked for our club it might be useful to you.
The following is a photograph of a typical SCR throttle installed at the London Model Railroad Group's layout. The
throttle has two reversing relays so that when the direction switch is in its centre position the throttle is disconnected
from the track. This is a club standard for all main line throttles.
The throttle boards are hung under the layout by hooks so that they could quickly be changed if a failure occurred.
This was a hold over from a previous throttle design that was trouble prone.
The power transformers were located in electrically safe enclosures to keep the weight of the throttle boards to a
minimum. Volt and Amp meters are connected at the terminal strip so that they are ahead of the relays.
Potentiometer Controlled Silicon Controlled Rectifier Throttle
The second schematic is a basic version of the SCR throttle circuit. It uses a potentiometer instead of push buttons
for control. All of the above set up instructions apply to this design as well except that the potentiometer is set to
maximum when adjusting the 50K trimmer.
Potentiometer Controlled SCR Throttle Schematic
The "MoAT" Project Throttle.
The third schematic is a throttle that was built for the London Model Railroad Group because of a quest for more
power (amps) to triple head an all brass 21 hopper coal drag with scratch built Steam locomotives.
A quest ranking somewhere between that for the Holy Grail and the Golden Fleece. The fact that the transformer (22
Volts and 15 Amps) that powers this throttle just happened to appear at the right time helped get it off the ground.
AC motor speed controller kit - K2636
This kit was designed to control the speed of AC motors with carbon brushes, anything from drills to saws to vacuum
cleaners. Unlike other circuits such as normal dimmers the kit performs a phase cut only once per period. The
moment of cutting determines the speed, which can be adjusted from 5% to 95%.
The kit provides high torque even at low speeds. RFI is suppressed to eliminate noise and interference. The circuit
controls both low voltage (from 24VAC to 240VAC at 5.5A) AC motors and mains voltage (110VAC or 220VAC)
loads.
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The supply and load circuits are electrically isolated from each other for safety and reliability. The control circuit is
powered by the mains, but the load supply may be derived from a different AC source. Both voltages should be the
same frequency and the same phase or opposite phase.
Parts list:
 R13: 27 ohm resistor
 T4: BC517 transistor
R1: 4.7K resistor
 R14: 390K resistor
 TRI1: BT137F-600 Triac
R2: 3.3K resistor
 RV1, RV2: 100K trim potentiometers
 F1: 250mA slow fuse
R3: 680 ohm resistor
 C1: 470uF electrolytic capacitor
 F2: 5A slow fuse
R4, R5: 22K resistors
 C2: 1uF electrolytic capacitor
 L1: 50uH/1kHz coil
R6: 1.5K resistor
 C3: 100nF capacitor
 Trafo1: 2x6V/1x0.3A
R7: 47K (50Hz), 10K (60Hz)
 C5: 47nF capacitor
 Heatsink for the triac
 terminal blocks (VAC, load and
R8: 100K resistor
 C6: 100nF/400V capacitor
mains)
R9: 100 ohm resistor
 C7: 47nF/400V capacitor
 J1, J2 mains voltage jumpers
R10: 120 ohm resistor
 D1, D2, D7: 1N4007 diodes
printed circuit board
R11: 68 ohm resistor
 D3-D6: 1N4148 diodes
R12: 1K resistor
 T1-T3: BC547B transistors
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Sun light control automatically using SCR
This circuit controls the turn the power off consumption in home automation. If it is daytime working to break the
circuit. But at night is connected to a working electrical AC 220 volts. Such as the opening and closing of the bulb.
This lamp will illuminate when the light bulb goes off into the evening and on beginning to dawn.
How
circuit
works
The circuits ready working. When the male plug, or for the circuit to the AC line power at 220 volts. The plug socket is
connected to appliances in the home. Or connect with bulbs. The circuit is based on the brightness of the light incident
on the LDR. By the features is as follows.
When LDR received an indirect light. It will have a low resistance causes a current flow through too much or through
to a ground fully. Makes a capacitor C1 look like short circuit. As a result, the transistors Q1 and Q2 not works. So not
have a voltage pulse to trigger a SCR1(T106) or stop working so as to short-circuit the AC power. Makes electrical
components, or lamps connected to the plug socket. Or the connector points SK1. Therefore not working or notice a
light bulb goes out.
But when the LDR is received the sun light. The it ‘s body will has the high resistance. Makes the current flowing
through the less. So flow to store at the C1. So have a voltage across it to use as the bias voltage to the transistors
Q2(BC337) and Q1(BC327) runs. So has the voltage pulse to trigger to provide the SCR1 also works. Therefore
virtual circuits is connected to the AC power. Makes the electrical components or the lamp that connected with the
plug socket or the point-SK1 or noticed the lamp is lit.
Additional, the LDR stands for the Light Dependent Resistor. Acts as a general sensor light. It is a type of resistor
whose resistance value changes according to the intensity of incident light transmitted to it. If there is much light, the
resistance is low, (as a result of the current through a lot). If low light, the resistance is high, (as a result, less current
flow). The sensitivity of the circuit will adjust the variable resistor VR1.
Electrical appliances or light bulbs that are connected to a plug socket or points combination with SK1 about not
exceed 200 watts. Which depends on the tolerance power of diode D1, D4 or D2, D3 and SCR1. When working AC
circuits to flow seamlessly through these devices, particularly the diode number 1N4007 will allow current to flow only
up to about 1 amp.
Do not install the LDR to the direct exposure to the light from the lamp will turn on-off. Provides been specialized the
normal bright light only. Or the the back lamps, the light from the light bulbs.
Value of resistor R controls duration of time delay provided by RCA 40841 dual-gate FET in SCR trigger circuit, with
SCR in tum serving to triggertriacfor handling highcurrent resistive or inductive AC loads. Maximum delay of 5 min is
obtained when R is 60 megohms (IRC type CGH or equivalent resistor). Timing is accurate within 10% over
temperature rangeof -25℃to +60℃. D3 should be rated 60 V Use any SCR capable of handling triactrigger
current,rated 60 V.- Linear Integrated Circuitsand MOS/FET,s, RCA Solid State Division,Somerville,NJ,1977,p435437.
Battery charger circuit using SCR.
Simple battery charger based on SCR is shown here.Here the SCR rectifies the AC mains voltage to charge the
battery.When the battery connected to the charger gets discharged the battery voltage gets dropped.This inhibits the
forward biasing voltage from reaching the base of the transistor Q1 through R4 and D2.This switches off the
transistor.When the transistor is turned OFF,the gate of SCR (H1) gets the triggering voltage via R1 & D3.This makes
the SCR to conduct and it starts to rectify the AC input voltage.The rectified voltage is given to the battery through the
resistor R6(5W).This starts charging of the battery.
When the battery is completely charged the base of Q1 gets the forward bias signal through the voltage divider circuit
made of R3,R4,R5 and D2.This turns the transistor ON.When the Q1 is turned ON the trigger voltage at the gate of
SCR is cut off and the SCR is turned OFF.In this condition a very small amount of charge reaches the battery via R2
and D4 for trickle charging.Since the charging voltage is only half wave rectified ,this type of charger is suitable only
for slow charging.For fast charging full wave rectified charging voltage is needed.
Circuit diagram with Parts list.
AC Dimmer for Lamp 6.3V
This the circuit AC dimmer low voltage For lamp 6V. While this friends may don’t see the advantage of this circuit. But
I thinks first step advantage be something get learn the work of Triac. And have tall safety , because of use AC Low
Voltage. Which the work is simple be The UJT Q1 will do the frequency give Triac work or make Lamp the bright. By
have work rate of Triac can control with R1 or Be something dimmer there. You will may apply with the size Voltage
the other all right. The Q1 use UJT – 2N4891 or other. A friend may gain an advantage from AC Dimmer for Lamp 6V
, please sir.
AC lights dimmer with triac
This circuit has can to turn down a light bulb arrives at 100W. If Triac there is tall temperature should hold Heat Sink or
let off the heat. The Diac be diode that perform be formed encourage or Trigger Diode 2 kinds are way or
Bidirectional. The VR1 use for fine decorate turning down fire. Caution this circuit must is in a box closes all the time
that have the electricity flows through.
In figure 2 well than the first circuit
Operation of the circuit be Lamp L1 is adjusted by adjusting the light of VR1. This will serve to control the speed of
charging of C1, Because triac will work. When C1 has charged to the voltage at the triac work.When adjusting the
VR1 C1 will charge as little faster lamp is lit.If the adjustment of VR1 C1 will charge very slowly.The little light bulb.
Because the triac does not work over the triac during the work.The light bulb will dim down by adjusting VR1.The R1 is
placed for protection VR1 prevent damage.The R2, C2 is used to eliminate signal disturbance. Both produced and
external circuit.
1200 Watt AC Dimmer by Triac Q4006LT
This is Power AC Dimmer 1200 watt size. It is use a triac Q4006LT. Friends ever tour is the foreign land has and to
ever reach rest a hotel. On bed head has will head bed fire decorates. It has a button opens-close and a button
controls the brightness with the equipment this/these be AC Dimmer follow our circuit can fine to decorate.
The VR1 for control the light besides when friends apply TRUE work. The Q1 -Q4006LT , should hold heat sink with
and should be careful specially prohibit catch one ( part ) which part in the circuit , because read will bump against the
electricity can suck. I hopes this circuit , friends can induce apply be AC Dimmer with electric other appliances bump
against emphasize kind coil heat equipment , be lucky please yes.
Typical home light dimmer uses a TRIAC
Triacs cannot control the high current values that SCRs can
Here is the actual view of the circuit above. Note the inductor and the capacitor are used for phase shifting and
noise filtering. Have you ever noticed the 60 Hz ringing sound that comes from light dimmers and sometimes the
filament of incandescent lights that are dimmer controlled? It is the result of the chopping of the sine wave feeding
the light.
The fan is trying to keep the environment cool (CPU, industrial process, engine) The Fan Speed Control circuit uses
2 thermistors as a voltage divider to control control the TRIAC trigger circuit. The fan speed is thus proportional to
the temperature.
Here a low voltage logic circuit is used to control a higher voltage
An Optocoupler is used to keep the low voltage circuit safe from the higher voltage.
AC
load
(heater
motor).
DC motor controller diagram with SCR and cmos ic
This is speed controller circuit of 12Volt DC motor.You can adjust the speed of rotation of the spindle motor from 5-60
cycles per minute. The work of circuit, The IC1 is nand gate ic type,It accepts the voltage from the bridge diode BD1.
But there is no filter to smooth current.The other in the pin 2.The VR1, C1 and R1 is a phase shift or time delay to slow
down,voltage from pin 3 to triggers pin the gate of SCR1 to work.Or conductors to the motor, causing it to rotate.
Speed of the motor, can be achieved by adjusting VR1.
The power supply input pin 14 of IC1 is filtered to smooth the current, by through D2 and C2. The D1 prevents the
noise from the motor. and D3 is reverse-voltage protection of motors. This can cause circuit damage. If the circuit is
used with a motor that consumes more power. Heat sink should be attached to BD1, D1 and SCR1, because heat up.
May cause equipment damage.
Phase-control
The most elementary application is a half-wave control circuit. The thyristor is acting both as a power control device
and as a rectifier, providing variable power to the load !luring the positive half cycle and no power to the load during
the negative half cycle. The circuit is designed to be a two terminal control which can be inserted in place of a switch.
If full-wave power· is desired as the upper extreme of this control, a switch can be added which will short circuit the
SCR when R r is turned to its maximum power position.
800W three-port two-way SCR light-reducing circuit
The MBS4991 two-way SCR switch is produced by the Motorola company, you can control the three-port two-way
SCR by using it. The 1MΩ resistance can change the three-port two-way SCR's angle of flow from 0°to 170°. When
the angle of flow is maximum, the power that adds to the load can be more than 97% of the full power. No matter
which position the tone potentiometer is, the first half cycle's angle of flow is the same as the rear half cycle's.
Xenon Strobe Light 110V by SCR
This is Xenon Strobe Light circuit, model continual use a tube Xenon at give many brightnesses. By can fine blink fast
or slow get , with VR1. By have SCR perform formed control the work and this circuit uses the fire AC 110 Volt or AC
220 Volt. But must use a pot transforms the sky decrease electricity pressure lower. The detail is other , see in the
circuit.