APPLICATION OF MOTORS TO ADJUSTABLE FREQUENCY DRIVES PART 1 Alan Lowe, Senior Electrical Consultant

2  RISE TIMES  REFLECTED WAVES  BEARING CURRENTS  CABLE SELECTION  IGBT NON-AGENDA

3 AGENDA  INTRODUCTION  NOMENCLATURE  WHY USE AFD  HORSEPOWER, SPEED, TORQUE  MOTOR CAPABILITIES & LIMITATIONS  TYPES OF LOADS

4 PRE-TEST

5 A “SPECIAL” MOTOR WILL BE REQUIRED FOR DRIVE APPLICATIONS: A. ALWAYS B. MOST OF THE TIME C. RARELY D. NEVER

6 A MOTOR APPLIED TO AN AFD MUST MEET WHICH OF THE FOLLOWING: A. NEMA M-G 1 PART 30 B. NEMA M-G 1 PART 31 C. IEEE 841 D. NEMA PREMIUM EFFICIENCY

7 OPERATING ON AN AFD A 100 HP, 1200 RPM MOTOR CAN DELIVER 100 HP A. BETWEEN 1200 AND 1500 RPM B. BETWEEN 600 AND 1200 RPM C. ALL OF THE ABOVE D. NONE OF THE ABOVE E. DON’T ASK ME—I JUST CAME FOR LUNCH

8 DRIVE NOMENCLATURE IS IT--- VSD, ASD, VFD, OR AFD ?

9 DRIVE NOMENCLATURE VARIABLE VS. ADJUSTABLE THE WEATHER OUTSIDE IS VARIABLE THE TEMPERATURE IN YOUR HOME IS ADJUSTABLE

10 DRIVE NOMENCLATURE “SPEED” VS. “FREQUENCY” THERE ARE MANY KINDS OF ADJUSTABLE SPEED DRIVES: DC MOTORS CONE PULLEYS STEAM TURBINE MECH. DIFFERENTIALS EDDY CURRENT CLUTCHES ADJUSTABLE VOLTAGE DRIVES ADJUSTABLE FREQUENCY DRIVES

11 DRIVE NOMENCLATURE BE CAREFUL-- “DRIVE” CAN MEAN ALMOST ANYTHING

12 DRIVE NOMENCLATURE DRIVE: THE EQUIPMENT USED FOR CONVERTING AVAILABLE ELECTRICAL POWER INTO MECHANICAL POWER SUITABLE FOR THE OPERATION OF A MACHINE. A DRIVE IS A COMBINATION OF A POWER CONVERTER (CONTROL), MOTOR, AND ANY MOTOR MOUNTED AUXILIARY DEVICES.

13 WHY USE AN AFD? A. THE PROCESS REQUIRES IT B. THE PROCESS CAN BE IMPROVED BY IT C. ENERGY SAVINGS D. EASIER ON DRIVEN EQUIPMENT

14 WHY USE AN AFD? E. ACCELERATION OF HIGH INERTIA LOAD F. TO AVOID FREQUENT MOTOR STARTING G. AS A REPLACEMENT FOR GEARING

15 WHY WORRY ABOUT THE MOTOR? WHAT’S DIFFERENT? A. CAN THE MOTOR PRODUCE THE REQUIRED TORQUE THROUGHOUT THE OPERATING SPEED RANGE? B. WILL THE MOTOR HAVE ADEQUATE COOLING AT LOW SPEEDS? C. WILL HARMONICS FROM THE DRIVE CAUSE THE MOTOR TO OVERHEAT?

16 WHY WORRY ABOUT THE MOTOR? WHAT’S DIFFERENT D. WILL THE MOTOR FLY APART AT OVERSPEED? E. WILL THE DRIVE VOLTAGE WAVEFORM DAMAGE THE MOTOR WINDINGS? F. WILL THE DRIVE VOLTAGE WAVEFORM DAMAGE THE MOTOR BEARINGS?

17 IT’S A DRIVE SYSTEM !

18 THE MOTOR WHAT DO WE MEAN BY A 100 HP, 1800 RPM MOTOR?

19 HORSEPOWER

20 MOTOR HORSEPOWER 1 HP MOTOR 33,000 FT-LBS/MIN 550 FT-LBS/SEC 746 WATTS / MOTOR EFFICIENCY

21 MOTOR HORSEPOWER

22 MOTOR HORSEPOWER

23 MOTOR HORSEPOWER Generally a motor can deliver:  Rated TORQUE at and below base rated speed.  Rated HORSEPOWER at and above base rated speed. But there are some LIMITATIONS!

24 NEMA MG-1  Part 30.2 GENERAL PURPOSE MOTORS USED WITH ADJUSTABLE-VOLTAGE OR ADJUSTABLE-FREQUENCY CONTROL OR BOTH  Part 31 DEFINITE PURPOSE INVERTER FED POLYPHASE MOTORS

25 LIMITATIONS: REDUCED COOLING NEMA MG-1 FIGURE S.F. MOTOR 1.15 S.F.

26 LIMITATIONS: HARMONIC HEATING NEMA MG-1 FIGURE 30-3 IT DEPENDS ON THE MOTOR. IT DEPENDS ON THE DRIVE. THERE’S NO ESTABLISHED METHOD OF CALCULATION.

27 MOTOR TORQUE vs. SPEED RATED TORQUE = HP x 5252 / RPM

28 MOTOR TORQUE vs. SPEED LRT per NEMA MG TABLE 12-2

29 MOTOR LOCKED ROTOR TORQUE

30 MOTOR TORQUE vs. SPEED P.U. TORQUE per NEMA MG1,

31 MOTOR PULL UP TORQUE NEMA MG PULL UP TORQUE FOR DESIGN A AND B MOTORS

32 MOTOR TORQUE vs. SPEED BD TORQUE per NEMA MG1,

33 MINIMUM BREAKDOWN TORQUE PER NEMA MG FOR DESIGN A & B MOTORS

34 BREAKDOWN TORQUE IS PROPORTIONAL TO (V/HZ) 2 ABOVE BASE SPEED BREAKDOWN TORQUE IS PROPORTIONAL TO (1/HZ) 2 STARTING WITH 175% AT 60 HZ YIELDS 77.7% RATED TORQUE AT 90 HZ.

35 LIMITATIONS: TORQUE NEMA MG-1 FIGURE 30-4 B.D. TORQUE = 77.7% T R 2/3T R x 3/2S R = HP R

36 TORQUE vs. SPEED

37 TORQUE vs. SPEED ON AFD

38 TORQUE vs. SPEED ON AFD

39 TORQUE vs. SPEED ON AFD

40 MOTOR TORQUE vs. SPEED

41 MAXIMUM SAFE SPEED

42 LIMITATIONS: MAX SAFE SPEED POLES / RPM200% / 120Hz150% / 90Hz125% / 75Hz 2 / 3600Up to 5 HPUp to 30 HPUp to 50 HP 4 / 1800Up to 20 HPUp to150 HPUp to 300 HP 6 /1200Up to 75 HPUp to 350 HPN/A ALLOWABLE OVERSPEED OPERATION BASED ON NEMA MG 1 TABLE 30-1

43 LOAD CHARACTERISTICS  VARIABLE TORQUE  CONSTANT TORQUE  CONSTANT HORSEPOWER

44 VARIABLE TORQUE LOAD  CENTRIFUGAL PUMPS  FANS

45 VARIABLE TORQUE LOAD AFFINITY LAWS FOR CENTRIFUGAL PUMPS

46 VARIABLE TORQUE LOAD

47 VARIABLE TORQUE LOAD

48 VARIABLE TORQUE LOAD 102% 65 HZ

49 SELECT MOTOR FOR VARIABLE TORQUE LOADS 1. MAKE SURE THE MOTOR CAN OPERATE SAFELY AT THE TOP SPEED REQUIRED BY THE LOAD. 2. MAKE SURE THE MOTOR CAN DELIVER THE REQUIRED HORSEPOWER AT THE TOP SPEED. 3. LOW END OPERATION IS NOT A PROBLEM.

50 CONSTANT TORQUE LOADS  CONVEYORS  POSITIVE DISPLACEMENT PUMPS  CRANES  PAPER MACHINE SECTIONS

51 CONSTANT TORQUE LOAD

52 SELECT MOTOR FOR CONSTANT TORQUE LOADS 1. MAKE SURE THE MOTOR CAN OPERATE SAFELY AT THE TOP SPEED REQUIRED BY THE LOAD. 2. MAKE SURE THE MOTOR CAN DELIVER THE REQUIRED TORQUE AT THE TOP SPEED. 3. BELOW 30 HZ GIVE YOURSELF SOME MARGIN, LIMIT LOADING TO 80% OF RATING. 4. BELOW 15 HZ CONSULT THE MOTOR MANUFACTURER.

53 CONSTANT HORSEPOWER  UNWIND STAND OF A WINDER  A CENTER WIND REEL  PUNCH PRESS

54 CONSTANT HORSEPOWER MOTOR MUST PROVIDE 165 FT-LBS AND RPM OR HP = 165 x /5252 = 4

55 CONSTANT HORSEPOWER

56 CONSTANT HORSEPOWER

57 CONSTANT HORSEPOWER

58 SELECT MOTOR FOR CONSTANT HORSEPOWER LOADS 1. MOTOR MUST BE ABLE TO DELIVER THE SPEED AND TORQUE REQUIRED AT THE FASTEST AND SLOWEST OPERATING SPEEDS. 2. THE MOTOR WILL BE OF SPECIAL DESIGN OR VERY MUCH “OVERSIZED”.

59 SELECT MOTOR FOR CONSTANT HORSEPOWER LOADS 3. ALL PARTIES MUST BE INVOLVED: a) DRIVE VENDOR b) MOTOR VENDOR c) DRIVEN EQUIPMENT VENDOR d) END USER

60 REMEMBER! IN OUR SOCIETY: IAS THE APPLICATION MATTERS

61 APPLICATION OF MOTORS TO ADJUSTABLE FREQUENCY DRIVES END PART 1

62 APPLICATION OF MOTORS TO ADJUSTABLE FREQUENCY DRIVES QUESTIONS? or

63 PPIC 2013 ANNUAL CONFERENCE PULP AND PAPER INDUSTRY COMMITTEE 2014 ANNUAL CONFERENCE ATLANTA, GEORGIA JUNE 23, 24 & 25