Adjustable electronic load-alarm relay
- Paducah, KY
- Kevil, KY
This invention is an improved electronic alarm relay for monitoring the current drawn by an AC motor or other electrical load. The circuit is designed to measure the load with high accuracy and to have excellent alarm repeatability. Chattering and arcing of the relay contacts are minimal. The operator can adjust the set point easily and can re-set both the high and the low alarm points by means of one simple adjustment. The relay includes means for generating a signal voltage proportional to the motor current. In a preferred form of the invention a first operational amplifier is provided to generate a first constant reference voltage which is higher than a preselected value of the signal voltage. A second operational amplifier is provided to generate a second constant reference voltage which is lower than the aforementioned preselected value of the signal voltage. A circuit comprising a first resistor serially connected to a second resistor is connected across the outputs of the first and second amplifiers, and the junction of the two resistors is connected to the inverting terminal of the second amplifier. Means are provided to compare the aforementioned signal voltage with both the first and second reference voltages and to actuate an alarm if the signal voltage is higher than the first reference voltage or lower than the second reference voltage.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- Assignee:
- United States of America as represented by United States Energy (Washington, DC)
- Patent Number(s):
- US 3934239
- OSTI ID:
- 862455
- Country of Publication:
- United States
- Language:
- English
Similar Records
Charge monitor for electric battery
Self-compensating voted logic power interface with tester
Related Subjects
electronic
load-alarm
relay
improved
alarm
monitoring
current
drawn
motor
electrical
load
circuit
designed
measure
accuracy
excellent
repeatability
chattering
arcing
contacts
minimal
operator
adjust
set
easily
re-set
means
simple
adjustment
generating
signal
voltage
proportional
preferred
form
operational
amplifier
provided
generate
constant
reference
preselected
value
aforementioned
comprising
resistor
serially
connected
outputs
amplifiers
junction
resistors
inverting
terminal
compare
voltages
actuate
signal voltage
alarm relay
serially connected
motor current
reference voltage
preferred form
electrical load
preselected value
operational amplifier
reference voltages
voltage proportional
improved electron
selected value
current drawn
/340/327/