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       Consultation, Design and Build - Control and Instrumentation


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Bespoke Instrumentation - Case Studies

Water In Oil Detector

JK Controls have designed, developed and built a device for detecting the interface between water and oil. 

A way of detecting if water is present beneath the waste oil and fat collected for recycling and processing into bio-diesel was required.  Our solution involved building a device with an LED array that illuminates as the probe passes through oil and encounters a layer of water.  The device is made of materials that resist corrosion and boiling water and can cope with a harsh operating environment.  A pair of handles are fitted for ease of use and to aid insertion through hard fats.  The detector is battery operated, with the batteries housed in a separate compartment to the electronics.  It will switch off automatically after 20 minutes to conserve battery life.  There are internal adjustments for changing the sensitivity (Span) of the detector and also for setting the zero of the LED array.  Click HERE for a PDF with further information and images.

Aircraft Wing Brake Test Rig

JK Controls have designed, developed and built bespoke instrumentation and controls for a test stand for a prototype aerolon brake.

The aerolon drive shaft is held by an electrically operated brake when not required to rotate.  The brake has to bring the shaft to a halt within 40mS of being de-energised.  For testing purposes the shaft is rotated by a motor at up to 1500 rpm.  The motor is driven by a variable speed inverter at a preset speed.  On de-energising the motor, the shaft free-wheels for a few msecs and the speed is measured.  The brake is then de-energised and the shaft monitored until it ceases to rotate.  Timers automatically start and stop during the braking event.

This project required several custom designed components where there were no suitable proprietary products available.  As the shaft stops within 40 msec. it only turns about one quarter of a  turn from running to stopped.  Therefore the speed was measured using a very fine resolution printed slotted wheel and a suitable optical detector.  Physical constraints prevented access to either end of the shaft, the slotted disk was therefore custom made, together with the high speed optical detector by JK Controls Ltd.  Using fast hardware processing the shaft was determined as stopped when the pulse repetition rate dropped below a threshold.  The timing and measurement logic was designed and built on to custom printed circuits.  During the braking period the brake torque is measured by a strain gauge and the peak braking torque, in both directions, is stored.  Analogue hardwired circuits were built to sample-hold for peak torque and initial speed stores.  The stored values are displayed on suitably scaled digital indicators.

The sequence of running up the motor, priming the data collection and timers, initiating the test and monitoring the results was handled by a small PLC.  Various safety interlocks are built in to prevent operation under unsafe conditions.  Great care was taken to minimise sensitivity to, and radiation of, electro-magnetic interference.

Brake Test Rig
Bespoke Instrumentation
Occulting Disk
Custom built control panels
Control Panel
Bespoke printed circuit boards
Peak Torque Detector
Custom built instrumentation
Optical Detector
Remote camera controls
Typical console opened up
Custom built control panelsA power plant company use many specialist techniques for plant inspections during overhaul periods.  One need was for an operator console to house the controls and monitors.  JK Controls Ltd built a pair of custom consoles that could vary the lighting and monitor the temperatures of the cameras and their inclination from normal within the plant.  The horizontal shift of one camera could also be altered remotely to adjust the stereoscopic imaging.

JK Controls have also built bespoke control consoles for video display, recording and camera monitoring.

Cable wrapper speed analysis
A specialty cable manufacturing company required a measurement of deceleration of cable insulation winding heads with a time resolution of a few milliseconds.  Access to the plant was extremely restricted.  JK Controls designed and manufactured signal conditioning equipment and a small custom transducer to run on the surface of the winding head.  The measured speed was recorded on a high speed recorder which could indicate any non-linearity in the deceleration and any over-run of the drive mechanism.

Generator loading monitor

Power station operators have to supply power to the National Grid within very tight margins.  If they run below target they suffer penalties, but if they supply above target they do not get paid for the excess energy.  To walk this tightrope during steady running is sometimes difficult, but to follow the moving target load after synchronizing and whilst raising load is much more difficult.

JK Controls have built a PC based monitoring system that enables the operator to input the type of run up and the target load and time.  This will then draw the load trajectory on the screen with tramlines to indicate the tolerance allowed.  Once synchronized, the generator load will be plotted on this screen in real time and the operator will endeavour to drive the plant to maintain the generator output within the tramlines. 

Retrofit Solutions - Case Studies

Legacy Alarm System Renewal
A power station's ageing alarm system had become obsolete due to the original manufacturer no longer being in business.  JK Controls provided a cost effective solution by analysing the existing system and then designing and building new solid-state based circuit boards to electrically emulate and be physically plug compatible with the original.

Original obsolete Alarm card

New plug compatible Alarm card

Vector Meter Retrofit
JK Controls have recently designed and built modern electronic Vector Meters to replace the original obsolete mechanical instruments in a Scottish power station.  The Vector Meters can be setup using jumpers to take either 4 - 20 mA or 0 - 10 Volt input signals.  The two input signals, mega Watts and mega VArs are galvanically isolated and displayed on a TFT screen mounted within the operators control desk.

Mechanical Vectormeter   Electronic Vectormeter

Original obsolete mechanical Vector Meter.            Modern replacement electronic Vector Meter.

SCADA Retrofit
JK Controls replaced an obsolete control system for a power station's generator/grid switchgear within a two day outage.  This was achieved by the manufacture of custom interfacing equipment which was plug compatible with the original system I/O connectors, thereby providing considerable cost benefits to the station in terms of downtime and future reliability.

Virtual Chart Recorders
Ageing and obsolete control room chart recorders at a power station in Kent had become unreliable and expensive to maintain.  JK Controls designed and built a virtual recorder system based upon PLC input equipment and three SCADA PC's driving twelve TFT liquid crystal monitors.  Each display emulated four multi-pen chart recorders and was mounted in an add-on section of control desk designed by JK Controls, which integrated with the operators original desk.  The resulting flexible data display system was provided at low cost compared to replacement costs for the existing recorders.

Contact Information: e-mail to info@jkcontrols.co.uk, or telephone +44 1732 522353  

Registered Address: JK Controls Ltd, The Barn, 65 High Street, East Malling, Kent, ME19 6AJ..  Reg. No. 3073964

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