Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
OVER-/UNDER-VOLTAGE PROTECTION OF ELECTRICAL APPLIANCES
#1

OVER-/UNDER-VOLTAGE PROTECTION OF ELECTRICAL APPLIANCES

.pdf   OVER-UNDER-VOLTAGE PROTECTION OF ELECTRICAL APPLIANCES.pdf (Size: 54.11 KB / Downloads: 127)
This circuit protects refrigerators as
well as other appliances from overand
under-voltage. Operational amplifier
IC LM324 (IC2) is used here as a
comparator. IC LM324 consists of four operational
amplifiers, of which only two operational
amplifiers (N1 and N2) are used
in the circuit.
The unregulated power supply is connected
to the series combination of resistors
R1 and R2 and potmeter VR1. The
same supply is also connected to a 6.8V
zener diode (ZD1) through resistor R3.
Preset VR1 is adjusted such that for
the normal supply of 180V to 240V, the
voltage at the non-inverting terminal (pin
3) of operational amplifier N1 is less than
6.8V. Hence the output of the operational
amplifier is zero and transistor T1 remains
off. The relay, which is connected to the
collector of transistor T1, also remains deenergised.
As the AC supply to the electrical
appliances is given through the normally
closed (N/C) terminal of the relay,
the supply is not disconnected during normal
operation.
When the AC voltage increases beyond
240V, the voltage at the non-inverting terminal
(pin 3) of operational amplifier N1
increases. The voltage at the inverting terminal
is still 6.8V because of the zener
diode. Thus now if the voltage at pin 3 of
the operational amplifier is higher than
6.8V, the output of the operational amplifier
goes high to drive transistor T1 and
hence energise relay RL. Consequently, the
AC supply is disconnected and electrical
appliances turn off. Thus the appliances
are protected against over-voltage.
Now let’s consider the under-voltage
condition. When the line voltage is below
180V, the voltage at the inverting terminal
(pin 6) of operational amplifier N2 is less
than the voltage at the non-inverting terminal
(6V). Thus the output of operational
amplifier N2 goes high and it
energises the relay through transistor T1.
The AC supply is disconnected and electrical
appliances turn off. Thus the appliances
are protected against under-voltage.
IC1 is wired for a regulated 12V supply.
Thus the relay energises in two conditions:
first, if the voltage at pin 3 of IC2 is
above 6.8V, and second, if the voltage at
pin 6 of IC2 is below 6V. Over-voltage and
under-voltage levels can be adjusted using
presets VR1 and VR2, respectively.
This circuit costs around Rs 110.
Reply

Marked Categories : yhs 004, under voltage pdf, ppt about voltage protection under relay, amplifier is zero and transistor t1 remains off the relay which, protection of electrical appliances, amplifier is zero and transistor t1 remains off, over under voltage protection, over under voltage protection of electrical appliances project, electrical system undervoltage protection, over under voltage protection of electrical, ppt of over under voltage overload protection of home appliance, topics of over voltage under protection the electrical appliances, ac undervoltage protection, over under voltage protection of electrical appliances pdf, voltage protection for appliances,

[-]
Quick Reply
Message
Type your reply to this message here.

Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  Investigation and Analysis of Inception Voltage and Field Distribution seminar presentation 1 25,638,297 22-09-2017, 11:06 AM
Last Post: jaseela123
  A Series Active Power Filter Based on a Sinusoidal Current-Controlled Voltage-Source project uploader 1 2,827 14-09-2017, 03:47 PM
Last Post: jaseela123
  Neural networks and fuzzy logic in electrical engineering control courses project uploader 1 54,810 13-09-2017, 02:24 PM
Last Post: jaseela123
  Basic Experiments in PID Control for Non-electrical Engineers pdf project girl 1 4,972 13-09-2017, 01:42 PM
Last Post: jaseela123
  SINGLE PHASE AC VOLTAGE CONTROLLER study tips 1 815 09-09-2017, 11:06 AM
Last Post: jaseela123
  POWER SYSTEM PROTECTION pdf study tips 1 1,445 09-09-2017, 09:08 AM
Last Post: jaseela123
  LM78XX Series Voltage Regulators project uploader 1 1,842 08-09-2017, 11:27 AM
Last Post: jaseela123
  Extra high voltage ac transmission engineering seminar paper 1 11,777 02-09-2017, 11:01 AM
Last Post: jaseela123
  synchronization and protection of alternators project uploader 1 2,833 31-08-2017, 01:13 PM
Last Post: jaseela123
  Measurement and simulation of the electric field of high voltage suspension insulator project report helper 1 5,347,746 29-08-2017, 11:20 AM
Last Post: jaseela123
This Page May Contain What is OVER-/UNDER-VOLTAGE PROTECTION OF ELECTRICAL APPLIANCES And Latest Information/News About OVER-/UNDER-VOLTAGE PROTECTION OF ELECTRICAL APPLIANCES,If Not ...Use Search to get more info about OVER-/UNDER-VOLTAGE PROTECTION OF ELECTRICAL APPLIANCES Or Ask Here

Options: