Baldor MN770 manual Section Set-Up Information, DC SCR Controls, Field Control, Feedback

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Section 5

Set-Up Information

DC SCR Controls

DC motors use voltage to obtain their speed and current to develop their output torque.

 

A DC SCR control must be able to supply the required voltage and current to operate the

 

motor under all conditions of load and speed.

 

Note: Do not assume that having the required horsepower is sufficient information to

 

size the control. You will need to know the maximum voltage and current. The

 

motor nameplate should be the source for the RMS (continuous) ratings but

 

actual measurements should be made to determine the maximum required

 

current and voltage with the elevator loaded to capacity.

Field Control

Remember that the Series 20H control's DC output is a maximum of 113% of input

 

voltage for the armature and up to 85% of input voltage for the field. This means that if

 

the field voltage is more than 195 volts for a 230 volt AC line, a single phase transformer

 

must be used to boost the AC input to the field power module. Some gearless elevator

 

DC motors have odd voltages which need to be supplied from special controls through

 

isolation transformers.

 

All Series 20H field power modules can be operated from 480 VAC or less, regardless of

 

the catalog or spec number of the control. The standard field power supply module is

 

rated for 15 amps maximum, but a 40 amp field power module is available as an option.

Feedback

Most elevator DC controls operate closed loop which means that the motor speed is fed

 

back to the control using a DC tachometer, encoder or resolver. The feedback device is

 

usually coupled to the motor shaft but also may operate from a wheel on the sheave. A

 

DC tachometer is the most common feedback device and this requires the EXB006A01

 

expansion board mounted in the Series 20H.

 

Gearless elevators often benefit from using encoder feedback due to the higher

 

resolution of the feedback signal during low speed (leveling) conditions. The Encoder

 

interface is built into in the Series 20H while a DC tach or resolver feedback requires an

 

expansion board. A DC tach may be used on a gearless elevator but it should be

 

optimized to give a high DC volts per RPM output.

 

Typical DC tachometers provide 50, 60, 100 or 200 volts DC output per 1000 RPM when

 

coupled 1:1 to the motor. Encoders are usually 1000 or 1024 pulses per revolution (PPR).

 

Note: The boosted voltage must be in phase with the incoming lines L1 and L2.

Initial Installation and Startup When installed in a panel, the Series 20H control should be located away from sources of heat and in an area where the keypad is visible and convenient to operate. See the Series 20H manual (MN720) for additional installation information, watts loss requirements, and other information regarding the selection of a mounting location. Any required expansion boards should be installed before applying power.

Preliminary programming should include setting the following:

1.Level 1 Input Block, Operating Mode.

2.Level 1 Output Block, Opto Output values.

3.Level 1 DC Control Block, all parameters.

4.Level 2 Output Limits Block, all parameters.

5.Level 2 Motor Data Block, all parameters. Other parameters will be set after final installation.

Note: In many elevator applications the BIPOLAR HOIST MODE is used with the elevator controller as well as an external S-Curve generator.

MN770

Set-Up Information 5-1

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Contents Elevator Application Guide MN770Table of Contents Ii Table of Contents MN770 Drive Definition Section General InformationIntroduction ModernizationsLimited Warranty Safety Notice Perform a ªMeggerº test. Failure to disconnect motor from VAC or 460 VAC maximum per control ratingUnderwriter Laboratory requirements Overview FeatureSection Technologies Drive Performance ComparisonDC SCR Control 20H Control15H Control Inverter21H Control 17H & 18H Controls Vector22H Control Section Application Considerations Electric Drives Operating Mode Common Control FeaturesAvailable Operating Modes US Measurement System Elevator Motor Horsepower SelectionMetric Measurement System Motor Sizing Dynamic Brake Hardware Selection OCW =Encoder Retrofit Section Hardware InformationGeneral Considerations Cable PreparationEncoder Cables Encoder End Control End Encoder Cable ConnectionDifferential Connections Single Ended ConnectionsBuffered Encoder Output Field Control Section Set-Up InformationDC SCR Controls FeedbackFinal Installation Overload = Fault Following Error = on Torque Proving = onFinal Adjustments Speed Command Armature EnableBrake Release Signal ContactorInitial Installation and Startup Inverter ControlsPage TURN-ON Vector Controls Balanced Car Test Full Load TestFinal Wiring Connections Series 18H Control ConsiderationsProcedure Initial Set-upRated Motor Load Slip Adjustment Value Slip Adjustment ValueFinal Set-up Power Up/Down Sequence for Vector Controls Pre-Installation Tests DateVector Control Worksheet Set-Up Information MN770 Section Troubleshooting Electrical Noise Display R-C Snubber Circuit & twisted-pair Electrical Noise Considerations10HP, 460VAC Drive 30HP, 500VDC Drive, Shielded 10 Isolated Mounting Method Analog Signal Wires Wiring PracticesPower Wiring Encoder CircuitsOptical Couplers Optical IsolationPlant Ground Fiber OpticsAppendix a Load Weighing / Torque Feed ForwardTable A-1 Description of OperationAppendix B Serial CommunicationsAppendix B MN770 Appendix C Elevator Industry GlossaryPage Page Appendix C MN770 Box  Baldor Electric Company MN770 97 C&J300

MN770 specifications

The Baldor MN770 is an impressive industrial motor designed for a variety of applications, showcasing robust construction and advanced technology. Known for its reliability and efficiency, the MN770 is manufactured by Baldor Electric Company, a prominent name in the electric motor industry.

One of the main features of the MN770 is its high-efficiency design. This motor adheres to stringent efficiency standards, helping to reduce energy consumption and lower operational costs. It typically meets or exceeds NEMA Premium Efficiency ratings, making it an excellent choice for businesses looking to optimize their energy use.

The MN770 motor is built with a durable cast iron frame, ensuring longevity and resistance to harsh operating conditions. Its weatherproof design is ideal for both indoor and outdoor applications, making it suitable for various environments, including manufacturing plants, water treatment facilities, and agricultural operations.

Another significant characteristic of the MN770 is its versatility. The motor is available in a range of horsepower ratings, allowing users to select the model that best fits their specific needs. Additionally, it offers various mounting configurations and voltage options, further enhancing its adaptability for diverse applications.

The motor utilizes advanced insulation systems and cooling technologies to ensure optimal performance and a longer lifespan. The robust design helps to dissipate heat effectively, enabling the motor to operate efficiently even under heavy loads. This characteristic is essential for applications requiring continuous operation without compromising reliability.

Moreover, the Baldor MN770 incorporates advanced design features such as precision-balanced rotors and high-performance bearings. These characteristics contribute to reduced vibration and noise levels, promoting a quieter working environment and improving overall operation efficiency.

In summary, the Baldor MN770 motor stands out due to its high efficiency, robust construction, versatility, and advanced technologies. Its ability to perform reliably in various industrial applications makes it a popular choice among engineers and facility managers. Investing in the MN770 not only enhances operational efficiency but also supports sustainability efforts by reducing energy consumption in industrial environments.
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