GE SR469-P5-HI-A20-E | Motor Management Relay, 5A CT

Description

Key Technical Specifications

Product Introduction

When a medium-voltage motor trips on thermal overload at 2 AM and nobody can tell you whether it was a real overload, a stuck rotor, or a bad RTD reading, you need a relay that logs the event and shows you the data — not one that just latches a trip light. The SR469-P5-HI-A20-E is GE Multilin’s motor management relay built around that exact problem. It combines protection functions (thermal overload with hot/cold curves, jam/stall detection, phase loss/unbalance, negative sequence, ground fault) with management features (RTD temperature trending, starts-per-hour counting, 4–20 mA analog retransmission to DCS) in a single panel-mount unit.

The “P5” in the part number means universal power supply — it accepts 70–265 VAC or 90–300 VDC, which simplifies spare parts inventory across sites running mixed control voltages. The “HI” designates the enhanced front panel with a 40-character LCD, dedicated alarm/trend keys, and a digital keypad for local setpoint changes. The “A20” option pack adds isolated 4–20 mA analog outputs so you can retransmit motor current, thermal capacity used, or kW draw directly to your DCS without a separate transducer. The trailing “-E” indicates an enhanced enclosure variant. If your application demands harsh-environment conformal coating, the “-H” suffix variant (SR469-P5-HI-A20-E-H) adds that protection.

GE SR469-P5-HI-A20-E

QA/QC Transparency SOP

For surplus SR469 units, a credible pre-shipment test sequence:

1. Intake & Origin Verification — Confirm the label reads SR469-P5-HI-A20-E with correct option codes. Check for GE Multilin branding, serial number, firmware revision stamp, and date code. Inspect the panel face for cracked LCD, damaged keypad buttons, or bent terminal pins.
2. Visual & Mechanical Inspection — Verify the panel-door mounting cutout dimensions match (approximately 192 × 192 mm). Confirm the sealed pull-out handle operates without binding. Check rear terminal blocks for corrosion, stripped screws, or missing shorting blocks on CT inputs.
3. Live Functional Testing — Apply rated control power (verify AC or DC range matches the P5 supply). Confirm the LCD powers up and displays the main menu. Navigate through setpoint groups using the keypad. Inject a simulated 5A current into the phase CT inputs using a test kit and verify the relay reads and displays current values within ±2% accuracy.
4. Analog Output & Communication Tests — With simulated current applied, measure the 4–20 mA analog outputs with a calibrated multimeter (Fluke 87V or equivalent). Confirm the output scales correctly across the configured range. Connect via RS-485 to a Modbus master and verify register reads complete without timeout.
5. Final QC & Anti-Static Packaging — Clear any site-specific setpoints to factory defaults (or document the existing configuration if the buyer requests it). Package in ESD-safe bag with rigid foam protection for the front panel LCD and rear terminals. Include a test report documenting power-up status, current measurement accuracy, analog output calibration, and Modbus communication results.

Field Engineer Gotchas

Gotcha #1: CT secondary rating mismatch.
The “P5” in this part number means 5A phase CT secondaries. If your motor’s existing CTs are 1A secondary, this relay will read incorrectly or not at all. Always verify your CT ratio and secondary rating before ordering. I have seen a plant order three of these only to discover their switchgear used 1A CTs — the relays had to be returned.

Gotcha #2: Thermal capacity bias settings causing nuisance trips.
The uses a thermal model with hot/cold curve ratios (typical default 16/18 = 0.89) and an unbalance bias K-factor. If the K-factor is not calculated correctly for your motor’s locked rotor current, the relay will overestimate thermal stress during unbalanced voltage conditions and trip prematurely. The K-factor formula is approximately 230 divided by the square of the per-unit locked rotor current. Verify these settings against the motor nameplate data before commissioning.

Gotcha #3: RTD wiring errors on 3-wire vs. 4-wire configurations.
The relay supports up to 12 RTD channels, but mixing Pt100 and Ni120 sensors or wiring 3-wire RTDs into 4-wire terminals (or vice versa) will produce false temperature readings. A bad RTD reading can inhibit motor starts or trigger false bearing temperature alarms. Label every RTD cable at both ends and verify the sensor type matches the relay’s RTD configuration setting.

Gotcha #4: Analog output burden limit.
The A20 analog outputs are specified at 1200 Ω maximum burden. If your DCS analog input card has a high input impedance or there is excessive loop resistance in the cable run, the 4–20 mA signal will clip or saturate. Measure the total loop resistance before assuming the relay output is faulty.

GE SR469-P5-HI-A20-E

Application Scenarios

• Medium-voltage pump motors in water/wastewater treatment — Protecting 4.16 kV or 13.8 kV pump motors where thermal overload, jam detection, and RTD bearing temperature monitoring must integrate with plant SCADA via Modbus RTU and 4–20 mA retransmission.
• Petrochemical compressor drivers — Managing large induction motors on gas compressors where starts-per-hour supervision, negative sequence protection, and stator RTD monitoring prevent catastrophic winding failures during repeated restart attempts.
• Mining conveyor drives — Providing stall/jam protection and phase unbalance detection on long-distance conveyor motors operating in high-humidity, high-vibration environments where the 95% non-condensing humidity rating matters.

Case Study (Anonymized): A power plant’s ID fan motor (4.16 kV, 1250 HP) kept tripping on thermal overload after 15–20 minutes of run time. Operations blamed the motor. Maintenance replaced the RTDs. The relay showed thermal capacity reaching 100% with no obvious overload. Root cause: the unbalance bias K-factor had been left at the factory default instead of being calculated for the motor’s actual locked rotor current of 6.31 × FLA. The relay was overestimating rotor heating from normal voltage unbalance. Recalculating and entering the correct K-factor (approximately 230 ÷ 6.31² ≈ 5.8) eliminated the nuisance trips. The motor ran clean after that.

FAQ

What does each part of the part number mean?
is the relay family. P5 = 5A phase CT secondaries. HI = enhanced front panel with 40-character LCD and keypad. A20 = 4–20 mA isolated analog output option pack. E = enhanced enclosure variant. If you see an “-H” suffix appended (-P5-HI-A20-E-H), that adds harsh-environment conformal coating.

Is this relay compatible with 1A CT secondaries?
No. The “P5” designation means this specific configuration is built for 5A CT secondaries. If your installation uses 1A CTs, you need a different configuration (typically designated with a “P1” in the part number). Do not attempt to adapt 1A CTs to a 5A relay — the readings will be wrong and protection will not function correctly.

Can I use this relay on low-voltage motors?
The is designed primarily for medium-voltage motors, but the protection functions (thermal overload, phase unbalance, ground fault, etc.) are applicable to LV motors as well. The key constraint is that your CTs and VTs must match the relay’s input ratings. Verify with the GE Multilin application guide for your specific motor voltage class.

What communication protocols does this relay support?
The supports Modbus RTU over RS-485 for DCS/PLC integration and has an RS-232 front service port for local configuration (9600 baud default, programmable up to 19,200 baud). It does not have native Ethernet or Modbus TCP — if you need Ethernet connectivity, you will need an external protocol converter or a different relay platform.

Is this relay still manufactured by GE?
The -P5-HI-A20-E circulates primarily through surplus and aftermarket channels as of available data. Contact GE Multilin (now part of GE Vernova) directly to confirm current production status and whether a successor platform (such as the SR489 or Multilin 869) is recommended for new installations.

How do I clear a latched trip and reset the relay?
Use the dedicated Reset key on the enhanced front panel, or send a reset command via Modbus. Before resetting, read the event log on the LCD to identify the trip cause — resetting without understanding the fault can lead to repeated trips or equipment damage. If the relay trips repeatedly on the same fault, do not keep resetting; investigate the root cause.

The SR489 is a higher-end motor management relay in the same GE Multilin family, offering additional protection elements (such as differential protection), more analog I/O, and enhanced communication options. The covers the majority of standard MV motor protection needs at a lower cost. Choose based on your protection scheme requirements — if you need motor differential, go SR489; if you need thermal overload, stall, unbalance, and RTD monitoring, the handles it.