Author: axcontrol

Hardware Comparison: Multilin 469 vs. Multilin 369

GE’s Multilin Motor Management Relays provide protection and monitoring for three-phase motors. They also provide protection for their associated mechanical systems.

Close up of a Multilin 369 Motor Management Relay.
GE Multilin 369 Motor Management Relay

Introduction

The GE Multilin 369 Motor Management Relay Series is designed with customizable relays. The units can protect three-phase motors and also offer monitoring applications.

Functional Summary Multilin 369

  • Display: 40 Character, Alphanumeric LCD
  • Status Indicators: 4 Output LEDs. Service LED, 5 other LEDs
  • Keypad: 12-buttons, including Help Key.
  • Interface: RS-232 comm port, Baud rate 120 to 19200
  • Case: Corrosion and flame-retardent
  • Digital Inputs: standard
  • Analog Inputs: Available
  • Current inputs: standard
  • Ground CT inputs: standard
  • Ports: 3 x RS485, Baud rate 1200 to 19200
  • RTD Inputs: available
  • Profibus Port: available
  • Backspin detection: available
  • Fiber Optic Data Link: available
  • Voltage Inputs: available

Protective Functions Multilin 369

Motor protection including:

  • Standard phase overload curves
  • Programmable (custom) overload curves
  • current unbalance

Management functions including:

  • Pre-trip data, to 40 events
  • starts per hour
  • time between starts
  • mechanical stall and jam
  • statistical data
  • backspin detection
  • flash memory
  • power metering (optional)

Technical Specifications Multilin 369

  • Control power: LO = 20 to 60 VDC, 20 to 48 VAC at 50/60 Hz, HI= 50 to 300 VDC, 40 to 265 VAC at 50/60 Hz
  • Power: Nominal: 20 VA, Max 65 VA
  • Fuse: T 3.15 Amp H 250 V, Timelag high breaking capacity
  • Operating Range: -40 to +60 Celsius
  • Operating Range w/Profibus: +5 to +60 Celsius
  • Humidity: up to 95%, non-condensing
  • IP50
  • Overvoltage Cat. II

Close up of a GE 469 Multilin Motor Management Relay
GE Multilin 469 Motor Management Relay

Introduction

The GE Multilin 469 Motor Management Relay is used to manage and protect motors of many HP ratings.

Functional Summary Multilin 469

  • Display: 40 Character, Alphanumeric LCD
  • Status Indicators: 6 Output LEDs, 8 Motor Status LEDs, 8 other LEDs
  • Keypad:Alphanumeric with Help button, plus +/- value keys. Message toggle keys. Enter, Menu, Escape, and Reset Key.
  • Interface: RS-232 comm port
  • Case: draw-out, IP40-X
  • Digital Inputs: 9 opto-isolated
  • Analog Current Inputs: specifications vary
  • Differential Current Inputs: Primary, 1 to 5000 A. Secondary, 1 A or 5A.
  • Ground CT inputs: Primary, 1 to 5000 A. Secondary, 1 A or 5 A.
  • Phase Current Inputs: Primary 1 to 5000 A. Secondary, 1 A or 5 A.
  • RTD Inputs: 3 wire RTD types
  • Voltage Inputs: 273 VAC full scale
  • Ports: 2 x RS485
  • Modbus: Modbus RTU/half-duplex
  • Ethernet: Available
  • DeviceNet: Available
  • Backspin detection: Restart Block can act as a backspin timer

Protective Functions Multilin 469

Motor protection including:

  • Overload Pickup using RTDs
  • Overload Curve
  • Short Circuit Trip
  • Ground Fault
  • Unbalance Alarming
  • Acceleration Trip
  • Stopped/Running Cooling Times
  • Stator and Bearing RTDs
  • Unbalance bias of thermal capacity and K factor
  • Hot/cold curve ratio

Management functions including:

  • Starts per hour
  • Time between Starts
  • Enable Start Inhibit
  • Mechanical jam
  • Remote Switch
  • Vibration & Pressure Switches
  • Remote Start/stop
  • Breaker failure

Technical Specifications Multilin 469

  • Control Power: LO = 20 to 60 VDC, 20 to 48 VAC at 48 to 62 Hz, HI= 90 to 300 VDC, 70 to 265 VAC at 48 to 62 Hz
  • Power: 45 VA (max) 25 VA (typical)
  • Fuse: 2.50 A 5 x 20 mm SLO-BLO HRC Littelfuse, high breaking capacity
  • Operating Range: -40 to +60 Celsius
  • Humidity: up to 90%, non-condensing
  • Altitude: up to 2000 m
  • Pollution degree: 2
  • IP: check case
  • Overvoltage: check case

Other differences you may want to consider. While the Multilin 369 can be used for small or medium induction motors and induction motors with a cyclic load, they cannot be used for large induction motors or induction motors via VFD as the 469 Multilin can. Additionally, the 469 offers synchronous motor protection that the 369 doesn’t have.

Also keep in mind the 469 has trip/close coil supervision. The 369 doesn’t offer that.

Both Multilin options are extremely versatile. Since they both offer a wide operating temperature range (-40 C to +60 C) they are suitable for a number of climate conditions. So even if your factory has to deal with Canadian cold or Australian heat, these motor management relays should work well inside its walls.

Have more questions? Se our GE Multilin FAQs blog.

Electric Motor Failures: How to Diagnose

Small DC Motor rotor showing windings
File:Small DC Motor Rotor.JPG” by Jjmontero9 is licensed with CC BY-SA 3.0.

When your electric motor fails, it can be difficult to know why. But there are quick tests you can use to easily diagnose problems.

Make sure to disconnect power from your electric motor before beginning. Power is not required. This step protects you and the equipment.

Motor Identification

Electric motors have a metal nameplate or tag riveted to the outside of the motor housing. This nameplate usually includes a lot of useful information, including

Nameplate for a Reliance Electric Servo Motor
Nameplate for a Reliance Electric Servo Motor
  • Manufacturer Name. Who made the motor.
  • Serial Number or Model Number. The model number tells you the make of your motor. The serial number uniquely identifies it.
  • RPM. Revolutions Per Minute. The output capability of your motor.
  • Horsepower. A rating of motor performance.
  • Voltage. The motor’s voltage requirements.
  • Current. How many amps the motor requires.
  • Frame Style. The unit’s physical dimensions.
  • Type. This can include NEMA ratings, cooling indications, etc.

A wiring diagram may also be included on the nameplate. In some cases, this tag will include the unit’s manual identification number, too.

Continue reading “Electric Motor Failures: How to Diagnose”

Surface Roughness and Turbine Blade Efficiency

Image of three wind turbines in fog. Wind turbine blade efficiency can be affected by surface roughness.
Turbine blades can lose efficiency if surface roughness becomes too pronounced.

Does surface roughness have an effect on turbine blade efficiency? Before we answer, let’s consider another theoretical.

Have you ever stood at the top of a mountain or hill and felt the wind slipping over the top of the summit around you? If you’ve done this in cold weather, you’ve probably looked for something like a tree or an outcropping to stand behind. Even smaller ones help. Such things act as windbreaks, parting the constant stream of air coming at you and softening it. But when nothing is in the way, air moving over the curved summit can feel like it’s been supercharged. It moves with an impressive ferocity of speed.

As it turns out, turbine blade efficiency acts much in the same way. And any sort of surface roughness acts like those outcroppings: parting, changing, and diverting the oncoming rush of air.

Although turbine blade design helps maintain robust performance under harsh conditions, wind turbine blades will show wear after only a short time. This includes chipping paint, edge erosion, and insect buildup. Offshore wind turbines are particularly susceptible to this wear due to UV radiation, salt spray, and other contaminants.

As this kind of roughness increases on blade surfaces, performance decreases. Performance issues include increased drag and decreased lift.

When roughness becomes more pronounced, some wind turbines may become subject to blade stall. Others may see a significant decrease in annual energy production.(1)

While surface roughness is not entirely to blame, such wear may be part of the underperformance issues plaguing many wind farms.

Blade erosion and surface roughness can be checked through regular inspections. This can pinpoint areas needing attention. Maintenance can then restore some original turbine efficiency.

(1) Ehrmann, Robert S., and White, E. B. Effect of Blade Roughness on Transition and Wind Turbine Performance.” United States. https://www.osti.gov/servlets/purl/1427238.

Need more information on industrial turbine replacement parts? We can help with that. Talk to our team today.