TR-7570 Transformer Protection Relay with 4 Channel Temperature Scanner

The TR-7570 is a single scanner unit intended for safe operation of medium voltage cast resin/dry type transformer. It is suitable for control room as well as marshalling box installation and is built for long and trouble-free operation under extreme conditions of services associated with transformer.

• Single scanner unit for three windings and fan Control, comes with Analog output (4-20 mA) for remote indication.
• Four output relays for Alarm (High), Trip (V. High), Fan on/off (Fan) & to warn against sensor open or wrong sensor connection (Fault).
• Memorises max. temperature even after power fail conditions
• Three numbers of user settable set-points can be used to control the cooling fan, to warn the user of high winding temperature and to shut down the transformer in case of excessive heating. Four numbers of Pt-100 RTD sensors allow the user to monitor the temperature of all the three phase windings plus one other critical point on the transformer like core. Alternatively, it can be used to check the ambient temperature or can be left as spare.
• TR-7570 is programmed to note and store maximum temperature of the winding. Facility extends to recall this information and to clear it for fresh recording.
• TR-7570 has one analog output signal (4-20mA) or an RS485 communication interface via MODBUS RTU slave depending on the variant selected. This can be configured to represent the temperature of any of the four channels or the temperature of the hottest channel.

Technical Specifications:

• Inputs: 4 nos. of RTD sensors (Pt-100, IEC-60751)
• No. of Set-points: Three (High, V. High, & Cooling Fan On)
• Temperature indication range: -50 to 300 °C
• Set point range: 1 to 300 °C
• Accuracy: +/- 1 °C
• Dead Band (relay differential): User settable (Range: 1 - 25 °C)
• Display Speed: User settable (Range: 1 -60 secs)
• Display: 3 Seven Segment 1/2" displays for displaying temperature
• 1 Seven Segment 1/2" display for displaying channel number

Mechanical:

• Overall Dimensions: 214 (H) x 265 (W) x 130 (D) mm
• Mounting: Wall mounting by 3 nos. M6 screws
• Weight: 3.5 kg approx. (unpacked)
• Enclosure: M.S. Sheet Box, powder coated, with acrylic viewing window (IP-52)

Electrical

• Supply Voltage: 90 - 270 VAC/DC (Optionally 20 - 50 VAC/DC)
• Outputs: Four relay contacts (one C/O contact for - Fault, Fan, High & V. High)
• One analog 4 - 20 mA output (corresponding to 0 to 200 °C max. load 300 ohms, linearity 0.5% w.r.t. local indication)
• Contact rating: For resistive load, 5A @ 230VAC & 0.5A @ 125VDC
• For inductive load, 5A @ 230VAC (cosθ = 0.4) & 0.3A @ 125VDC (L/R=7msec)
• Insulation: Insulation resistance shall be 100 Mohm or more when 500 VDC is applied between each terminal shorted together and earth. Controller will withstand 2KV rms at 50/60 Hz. for 1 min, applied between all relays & supply terminals shorted together & earth.
• Power consumption: Max. 15VA

Relay operations:

• Fault: Will energise after few seconds of power-on and de-energise on detecting fault condition. Fault relay will remain ON in normal conditions.
• Fan: Will energise if any channel's temperature exceeds Fan set point.
• High: Will energise if any channel's temperature exceeds High set point
• V. High : Will energise if any channel's temperature exceeds V. High set point
• Terminals: Combicon screw caged, suitable for 2.5 mm² solid conductors.

Environmental

• Operating conditions:
• Ambient temperature: -20 °C to 70 °C
• Relative Humidity : 95% Max non-condensing
• Storage Temperature: -20 °C to 85 °C
• Test conditions:
• Ambient temperature: 27 °C +/- 5 °C
• Relative Humidity: 20 - 80% non-condensing
• Vibration: 10-150 Hz, 0.0004" displacement

Variant:

• TR 7570C – Has a facility for computer communication using RS-485 with MODBUS RTU slave protocol, in lieu of 4-20mA signal.
• TR 7570 ( 20 – 50V ) – Input voltage range 20v  to 40v
• TR 7570 ( 85 – 265V) – Input voltage range 85v to 265v