Course # W 51 HVAC Motor Control Solutions Presenter: John Polites - Automation Engineer Wednesday, May 3 rd - 9:00 AM – 10:00 AM State College Room Topics of Discussion: –Motor Load & Starting Methods –Motor Control for HVAC Applications –Energy Savings with Variable Frequency Drives –Introduction to PF400 HVAC Drive

AC MOTOR LOADS

–Constant Torque –Variable Torque –Constant Horsepower AC Motor Load Types

Constant Torque Motor Loads

Variable Torque Motor Loads

Typical of Centrifugal Pumps and Fans Pumps: Hot Water, Chilled Water, Condenser Water, Distribution Fans: Supply, Return, Relief, Exhaust, Cooling Tower Fans Torque and Horsepower Drops As Square of Speed Reduction; Excellent Potential for Energy Savings with a VFD versus a throttling Valves, Dampers or Inlet Vanes Variable Torque Application Types

Two Pump Types: Positive Displacement Pumps Move fluid chamber to cause fluid to flow Constant Torque Load Profile Centrifugal Pumps Move fluid by rotation of an impeller Variable Torque Load Profile Hydronic Pumps: Hot Water, Chilled Water, Condenser Water & Distribution HVAC Pump Types

Components of the Pump System Pump Motor Coupling Base Plate Piping Valves Inlet Source –Above Pump –Below Pump Discharge Static Head

Pump Type and Applications

HVAC Systems

The purpose of an HVAC (heating, ventilating, and air-conditioning) system is to provide and maintain environmental conditions within an area called the "conditioned space." The commercial system selected for a particular application should endeavor to provide the optimum environment for employee comfort and productivity, process function, and good indoor air quality with energy efficiency and cost-savings HVAC Systems

Air Handling Systems –Air Handling Units (AHU), Rooftop Units (RTU), Makeup Air Units (MUA), Exhaust Fans (EF), Variable Air Volume Boxes (VAV),,fan unit (FU) Hydronic Systems –Chilled Water (CHW) – [Chillers and Pumping Packages] –Condenser Water (CW) – [Cooling Towers] –Hot Water (HW) - [Boilers and Pumping Packages] Building Automation System (BAS) –HVAC Controls, Direct Digital Controls (DDC), Energy Management System (EMS), Facility Management System (FMS) Types of HVAC Systems

HVAC Motor Control (Starters or VFDs) Typical Commercial HVAC Systems

Supply fan will be controlled by PF400 Controllers measure Static Pressure and send speed signals to both VFD’s VAV boxes located in each room distribute conditioned air Return fan will be controlled by PF400 Traditional Variable Air Volume (VAV) Air Handling Unit

These motors are controlled by a Variable Frequency Drive Variable Frequency drives Replace the wasteful Check valve system Chilled Water Pumping System

Valves replaced when drives are used Motors controlled by VFD’s in new applications Condenser Water Pump System

Building Automation Systems (BAS) > Controllers Send Output Commands to VFDs and Motor Starters: Start/Stop Control & Speed Commands > Run/Fault Commands Sends Status Commands for Starter Device to Controllers.

A pressure sensor within an air duct or pipe measures the system pressure As the pressure changes an analog signal is sent to the BAS The BAS sends a start stop and speed command to variable frequency drives (VFDs) or motor starters When valves and dampers close, the pressure rises in the ducts or pipes, which reduces the speed Basic BAS Systems Control Strategies

This is a typical view on a building automation computer screen showing the status of various points in an air handling system Building Automation System Graphic

Motor Starting Methods

Full Voltage Starting Reduced Voltage Starting –Wye - Delta Starters –Autotransformer –Soft Starters Variable Frequency Drives Types of HVAC Motor Starting Methods SMC- Flex

Full Voltage Starting Full Voltage Starting Characteristics –Contacts close immediately supplying full line voltage to motor. Advantages: –Lowest starter cost –Simple starter designs Easy to maintain and troubleshoot Disadvantages: –Inrush Current 6-10 times rated running current Issue when peak demand charges are enforced by utilities –Initial Torque Mechanically hard on system Reduced life of belts, gears Disconnect Fuses Contactor Overload Relay L1L2L3 T1T2T3

NEMA Rated  Serviceability  Contacts Replaceable  Flexible Overload Selection Emphasis on: IEC Rated Emphasis on:  Replacement  Contacts only replaceable on large sizes only  Conserve panel space  Class 10 Overload Protection IEC & NEMA Motor Starters

SMC-Flex Use SCR’s to ramp voltage supplied to motor over a user defined time period Advantages: Reduces inrush current Reduces starting torque Reduces mechanical stress on motor & loads Solid State Soft Starters

Reducing the Voltage Reduces the Current Reduction In Torque!! LRT 100% 0 Percentage of Full Speed (.5) 2 =.25 or 25% Soft Starter Speed Torque Curve

Manual Starters Range Overview –1HP, 115, 230, 277 VAC –0.75 HP, 115/230 VDC –1 or 2 Pole –Thermal Overload Ideal for small Fan and Pump Applications Commercial OEM Products

Adjustable Speed Drives

Solid State AC Variable Frequency = Variable Speed AC Motor DC Bus AC Input Fixed Frequency Inverter Converter AC Output Variable Frequency Variable Frequency Drives Basics Benefits Solid state technology Wide control options Small size power units Good efficiency Lower cost, smaller motors Retrofit existing motors Bypass capability VoltageHertzMotor RPM Base Voltage Base FrequencyV/Hz

To improve process control though speed and torque control To improve system efficiencies To extend life of equipment by reducing mechanical stress To Achieve Energy Savings on Fan and Pump Applications To meet the ASHRAE Energy Standards –Variable flow control on fan & pump systems Why Should I consider using a Variable Frequency Drive (VFD)?

Integral RS485 Communications Supports DSI Accessories Integral LCD Keypad Optimized for Commercial Fan and Pump Applications Stand-Alone Application Specific Features for Fans and Pumps Rated for Variable Torque Loads Packaged Allen Bradley PF400 HVAC Drive

Ratings – V, kW (3-50 Hp) – V, kW (3-150 Hp) 110% Overload for 60 seconds Enclosure –IP20 / UL Open 3-10 HP (240V AC) & 3-20 HP (480V AC) –IP30 / NEMA 1 / UL Type HP (240V AC) & 3-20 HP (480V AC) (with optional kit) HP (240V AC) & HP (480V AC) Environment –IP20 rated for 50 ° C –IP30 rated for 45 ° C PF400 Ratings

Main Input Disconnect 3 Contactor Full Feature Bypass with Disconnect 3 Contactor Basic Bypass with Disconnect Allen Bradley PF400 HVAC Drives Standard VFD

Configurable Keypad with local – remote start/stop and speed controls Compatible with Building Automation System Inputs/Outputs (Start/Stop, Speed and Feedback) Standard BAS Communications: –RS485, Modbus RTU, Johnson Controls N2 & Siemens P1 Future Communications: –Lonworks & Bacnet Process PI Inertia Ride Through Power Loss Flying Start S Curve, Accel & Decel profiles V/Hz Control Motor Overload protection Communication interfaces to Building Automation Systems Analog & Digital inputs & outputs Manual Bypass Capabilities Purge Start Input and Frequency Fire/Freeze Stat Interlock Inputs Variable Frequency Drive Control Capabilities Analog Output Dip Switches Analog Input Dip Switches 24V DC Source/Sink Relay OutputsAnalog and Discrete Wiring RS485 Ports

Starting Method % Voltage at Motor Terminals % Motor Starting Current% Line Current % Motor Starting Torque Lock Rotor Current Full Load Current Lock Rotor Current Full Load Current Lock Rotor Current Full Load Current Full Voltage Autotrans. 80 % tap % tap % tap Part Winding Star - Delta Solid State Variable Frequency Drive Motor Characteristics with Different Starting Methods

HVAC Motor Control Price Comparison Motor HPVFDSoft Starters NEMA Combination Starters IEC Combination Starters 5 $ 900 $ 1,100 $ 780 $ $ 1,000 $ 1,200 $ 813 $ $ 1,600 $ 1,195 $ $ 2,700 $ 2,400 $ 1,959 $ 1, $ 3,400 $ 2,800 $ 1,975 $ 1,513 Standard Features: 480 VAC, 3-Phase NEMA 1 Enclosure Input Disconnect Switch Motor Thermal Overload Protection

ENERGY SAVINGS WITH VFDs

Centrifugal Pump Energy Savings There are two methods used to accomplish the continuously varying flow: One method is throttling which changes the system curve by use of control or throttling valve. The other method is to vary the speed of the pump which modifies the pump curve. Building Automation System controls the pump starter or VFD and control valve based on HVAC sequence of operation.

Typical Pump Curves Pump Curves Throttled with Control Valves Pump Curves Controlled by a VFD Energy Savings with VFD’s (GPM Proportional Brake HP-Torque) Centrifugal Pump Energy Savings

Many air handling systems require operation at a wide variety of points. There are several methods used to modulate or vary the flow (or CFM) of a system to achieve the optimum points. These include: Cycling – As done in home heating systems. This produces erratic airflow and is unacceptable for commercial or industrial uses. Outlet Dampers – Control louvers or dampers are installed at the outlet of the fan. To control airflow, they are turned to restrict the outlet, which reduces the airflow. Variable Inlet Vanes – by modifying the physical characteristics of the air inlet, the fans operating curve is modified which changes the airflow. Variable Frequency Drives – By changing the actual fan speed, the performance of the fan changes producing a different airflow. Typical Fan Curves Fan Energy Savings Building Automation System controls the fan starter, control dampers and air system sensors based on HVAC sequence of operation.

Fan Curves with Outlet DampersFan Curves with Variable Inlet VanesFan Curves with VFD Fan Energy Savings

Sample Fan Energy Savings Report Energy Savings Software –( Energy Savings Report –VFD Specs –Energy Savings Calculations –Energy Savings Summary

VFD Energy Savings Software Tools

Schaedler Yesco Distribution HVAC Market

Plan & Spec Market –New Construction, Additions and Renovations –Track projects online through Harrisburg Builders Exchange –Mechanical plans/spec takeoffs for motor control that’s furnished by the HVAC contractor –Application coordination with mechanical equipment specs, building automation system sequences of operations and electrical power system plans Retrofit Market –Provided electrical energy solutions/products to Design/Build and Energy Service Teams i.e.: Variable Frequency Drives and Lighting Retrofit Solutions –VFD Fan or Pump Energy Savings Reports –VFD Replacement Program Schaedler Yesco Distribution - HVAC Market

Local Central PA Support with (5) Staffed Motor Control Specialist Product Guide Specifications & Submittal Packages Certified VFD Startup –VFD Checklist and Reports Onsite Training Available Spare Parts 24/7 Emergency Service Online Allen-Bradley Drives Technical Support – Motor Control Support

Questions ?

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