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A new series of fast motor load
controls designed specifically to monitor and protect valuable industrial
machinery and equipment has been released by sensing specialist Vydas
International Marketing.
The New Fast Response Digital Motor
Load Control manufactured by Load Controls Inc (USA) monitors true motor power
and detects common machinery problems such overloads, jams, obstructions, loss
of load, sudden load changes, missing tools or misplaced parts.
The PFR-1550 single set point
control, with high or low trip, detects overload or loss of load while PFR-1750
two set point control can trip an alarm and stop the machine with independent
relay outputs. The ROC-50 rate of change control is ideal for use with conveyers
and material handling equipment and detects sudden changes in load. This sensor
has a rate of change set point plus gross overload. The model CR-150 single
point current sensor is also available for special circumstances where it is
required to measure current gross overload only. All models have a 4-20mA output
to send load information to instrumentation, computers, chart recorders or data
logger’s etc. In order to avoid the possibility of nuisance trips during use
or at motor start up, all models also have adjustable digital start up and trip
timers.
These sensors are housed in a
compact rugged polycarbonate waterproof enclosure, with large digital display
(HP or KW) plus keypad and can be mounted on a door, inside a control cabinet or
surface panel mounted with included bezel kit. Settings can easily be seen on
the digital display at the touch of a button. Electrical connections are made
via convenient plug and socket terminal strips on the rear of the unit.
A unique range finder toroid is
included to allowing fast easy set up of motors up to 50HP connected directly.
Larger motors require optional current transformers to be used in conjunction
with the range finder toroid.
This product range is designed to
cope with the most difficult of motor load sensing tasks when other power
sensors and motor load controls are unable to function reliably. The control and
reliability of many process machines such as grinders, mills, mixers, rollers,
pumps, compressors, conveyers etc may be improved dramatically by sensing true
power instead of only current thus saving down time and loss of production. In
practice, it doesn’t matter however sophisticated the control computer system,
its overall system performance is very much dependant on the sensors at the
front end!!
Measuring power on the output of
variable frequency drives is a special case, as voltage and current transformers
do not work at low or high frequencies. In this case, waveforms on both the
input and output of a drive, are distorted and will cause gross errors in the
measurement of power. Where variable frequency or inverter drives are fitted the
"V" Series Fast Response Motor Load Controls should be used in
conjunction with the unique Universal Power Cell designed for this purpose. The
UPC is fitted with "Hall Effect" sensors that are not affected by odd
wave shapes or frequencies.
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