Ashridge Engineering

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Winding and Oil Temperature Indicators (WTI/OTI)


Ashridge design and manufacture the complete range of National Grid Approved winding and oil temperature indicators which provide high integrity protection, control and monitoring for power transformers.

The market leading Series 852 WTI’s continuously calculate the winding temperature (otherwise known as the hot spot) in the transformer and display the hottest winding.  The 852-013 OTI calculates and displays the oil temperature.

The extensive range includes alarm relay output, data logging, expired life, wide range of CT inputs, 1, 2, or 3 winding versions, dual display and an intelligent cooling control system with ‘deviation from normal’ alarms to ensure optimal asset life and protection for the transformer.   All models are easy to install or retrofit using either the integral  keypad or by using Ashridge’s configuration and set up software.

Please refer to our 852 Selection Guide to select the appropriate model for your requirements or refer to the summary below:

852Plus – National Grid approved model featuring watchdog + 5 relays, 2 analogue outputs, Modbus communications, intelligent cooling system, expired life and data logging.  The 852Plus is a single winding version with single display.

852-112 – Entry level WTI, featuring watchdog + 2 relays, 2 analogue outputs, Modbus and DNP3 communications, expired life and data logging.  The 852-112 is a single winding version with dual display.

852-113 – Featuring watchdog + 3 relays, 2 analogue outputs, Modbus and DNP3 communications, expired life and data logging.  The 852-113 is a single winding version with dual display.

852-116 – This model features watchdog + 6 relays, 2 analogue outputs, Modbus and DNP3 communications, intelligent cooling system, expired life and data logging.  The 852-116 is a single winding version with dual display.

852-118 – Featuring watchdog + 8 relays, 4 analogue outputs, Modbus and DNP3 communications, intelligent cooling system, expired life and data logging.  The 852-118 is a single winding version with dual display.

852-216 – This model features watchdog + 6 relays, 2 analogue outputs, Modbus and DNP3 communications, intelligent cooling system, expired life and data logging.  The 852-216 is a 2 winding version with dual display.

852-218 – Featuring watchdog + 8 relays, 4 analogue outputs, Modbus and DNP3 communications, intelligent cooling system, expired life and data logging.  The 852-218 is a 2 winding version with dual display.

852-318 – This model features watchdog + 8 relays, 4 analogue outputs, Modbus and DNP3 communications, intelligent cooling system, expired life and data logging.  The 852-318 is a 3 winding version with dual display.

852-338 – Top of the range, this model features watchdog + 8 relays, 4 analogue outputs, bottom oil and ambient (or tap changer) PT100 inputs, Modbus and DNP3 communications, intelligent cooling system, expired life and data logging.  The 852-338 is a 3 winding version with dual display.

852-013 – Ashridge’s Oil Temperature Indicator, featuring watchdog + 3 relays, 1 analogue output, Modbus and DNP3 communications and data logging, with single display.

Options and Accessories include:
·        Standard and custom PT100, (resistance temperature detectors)
·        Miniature measuring CT’s, (current transformers)

NEW 852 set up and configuration software available:
Ashridge now provide a configuration software utility which can be used to connect to any 852 Series WTI / OTI by using MODBUS to read and edit parameter settings. The software can also provide a download of the settings in TEXT format for incorporating in documentation. To use the software with a PC the Ashridge USB to RS485 configuration lead will need to be purchased. This is supplied as a set with the program and user manuals provided on a USB memory stick. The configuration software also contains a utility to enable download of the logs from the 852 memory.