Suggestion on How to Use • Industry Trainers are encouraged to use this material in their sessions • Download the presentation file • Print the Notes pages and read them as you view the presentation in the “Slide Show” view. In this way you see the slides in large format and have animation (when available) © 2015 Eaton. All Rights Reserved.. 1 Motor and Motor Circuit Protection © 2015 Eaton. All Rights Reserved.. Motor and Motor Circuit Protection • Agenda • Motor Circuit Characteristics • Protection from Overcurrents • Motor Circuit Requirements • Sizing OCPD’s • Back-up Overload Protection • Type 2 Protection © 2015 Eaton. All Rights Reserved.. 3 Motor and Motor Circuit Protection • How does a motor operate? • Starting • Normally • What do we protect against? • Overload • Short-Circuit © 2015 Eaton. All Rights Reserved.. 4 1000 Normal Operating Current Time in Seconds 100 10 Motor Inrush Curve 1 Inrush Current 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 5 1000 Time in Seconds 100 10 300 % Overload 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 6 1000 Time in Seconds 100 10 Short Circuit 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 7 Motor Circuit Requirements(NEC®) To Supply • 430.101- 430.113 (Part IX) • Disconnecting means • 430.52 Motor • Branch-Circuit Short-Circuit Protection • 430.32 Branch Motor • Overload Protection Overload M © 2015 Eaton. All Rights Reserved.. 8 Motor and Motor Circuit Protection • NEC® 430.102 • Location(Of Disconnecting Means) • (A) In sight from Controller • Branch-Circuit Short-Circuit Disconnect • (B) In sight from Motor • Branch-Circuit Short-Circuit Disconnect • Manual Motor Controller “Suitable as Motor Disconnect” • Exceptions provided if (A) is lockable in open position. © 2015 Eaton. All Rights Reserved.. 9 1999 NEC® Code Barrier, wall or isle with an obstruction Lockable Disconnecting Means Controller M © 2015 Eaton. All Rights Reserved.. 10 Requirement since 2002 NEC® Code In sight (of controller) disconnecting means ahead of controller required per 430.102(A) Barrier, wall or isle with an obstruction In sight motor disconnecting means required per 430.102(B) Controller M © 2015 Eaton. All Rights Reserved.. 11 Motor and Motor Circuit Protection • NEC® 430.52 • Branch-Circuit Short-Circuit Protection • (B) Must handle starting current • (C) Rating or Setting • (1) Table 430.52 • Exception 1: Next Higher size is permitted if the values from table 430.52 do not correspond to a standard size © 2015 Eaton. All Rights Reserved.. 12 Motor and Motor Circuit Protection • Table 430.52 Maximum Rating* Non timedelay Fuse1 Dual-Element (Time-Delay) Fuse Instantaneous Trip Breaker Inverse Time Breaker 300% 175% 800% 250% 1Non-Time-Delay also applies to Class CC fuses *Single-phase motors, AC polyphase motors other than wound-rotor, squirrel cage-other than Design B energy-efficient © 2015 Eaton. All Rights Reserved.. 13 Motor and Motor Circuit Protection • NEC® 430.52(C)(1) Exception 2: • If Motor Unable to Start, then size according to following, or next smaller size Non timeDual-Element delay (Time-Delay) Fuse 1 Fuse 400% 1Non-Time-Delay Inverse Time Breaker> Inverse Time Breaker< 100A 100A 300% 400% 225% 6016000A Fuse 300% also applies to Class CC fuses © 2015 Eaton. All Rights Reserved.. 14 Motor and Motor Circuit Protection • NEC® 430.32 (Overload Protection) • (a) More than 1 Horsepower. • (1) A separate overload device that is responsive to motor current. This device shall be selected to trip or rated at no more than the following percent of the motor nameplate full-load current rating. Motors with a marked service factor 1.15 or greater 125% Motors with a marked temperature rise 40 °C or less 125% All other motors 115% © 2015 Eaton. All Rights Reserved.. 15 MOTOR CIRCUIT DEVICES © 2015 Eaton. All Rights Reserved.. Motor and Motor Circuit Protection • What OCPD(s) can be used in a motor circuit? • Fuse • Circuit Breaker • MCP • Overload relay © 2015 Eaton. All Rights Reserved.. 17 1000 Time in Seconds 100 10 Motor Inrush Curve 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 18 1000 MCP at minimum setting Time in Seconds 100 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 19 1000 MCP at minimum setting Time in Seconds 100 10 Motor Inrush Curve 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 20 1000 MCP at maximum setting Time in Seconds 100 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 21 1000 MCP at maximum setting Time in Seconds 100 10 Motor Inrush Curve 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 22 1000 Time in Seconds 100 10 300 % Overload 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 23 1000 Time in Seconds 100 Motor Damage Curve 10 1 0.1 0.01 1 10 100 1000 Current in Amperes © 2015 Eaton. All Rights Reserved.. 24 1000 Time in Seconds 100 Motor Damage Curve 300 % Overload 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 25 1000 MCP at maximum setting Motor Damage Curve 300 % Overload Time in Seconds 100 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 26 1000 15A Circuit Breaker Time in Seconds 100 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 27 1000 15A Circuit Breaker Time in Seconds 100 10 Motor Inrush Curve 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 28 1000 15A Circuit Breaker Time in Seconds 100 Motor Damage Curve 300 % Overload 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 29 1000 NON-2 Amp Time in Seconds 100 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 30 1000 NON-2 Amp Time in Seconds 100 10 Motor Inrush Curve 1 0.1 0.01 1 10 100 1000 Current in Amperes © 2015 Eaton. All Rights Reserved.. 31 1000 NON-5 Amp Time in Seconds 100 10 1 0.1 0.01 1 10 100 1000 Current in Amperes © 2015 Eaton. All Rights Reserved.. 32 1000 NON-5 Amp Time in Seconds 100 10 Motor Inrush Curve 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 33 1000 NON-5 Amp Time in Seconds 100 Motor Damage Curve 300 % Overload 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 34 1000 Time in Seconds 100 10 1 Overload Relay 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 35 1000 Time in Seconds 100 10 Motor Inrush Curve 1 Overload Relay 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 36 1000 Time in Seconds 100 1 Motor Damage Curve 300 % Overload 0.1 Overload Relay 10 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 37 1000 MCP at maximum setting Motor Damage Curve 300 % Overload Time in Seconds 100 10 1 Overload Relay 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 38 1000 15A Circuit Breaker Time in Seconds 100 1 Motor Damage Curve 300 % Overload 0.1 Overload Relay 10 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 39 1000 NON-5 Amp Time in Seconds 100 1 Motor Damage Curve 300 % Overload 0.1 Overload Relay 10 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 40 1000 FRN-R-1-6/10 Time in Seconds 100 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 41 1000 FRN-R-1-6/10 Time in Seconds 100 10 Motor Inrush Curve 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 42 1000 FRN-R-1-6/10 Time in Seconds 100 Motor Damage Curve 300 % Overload 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 43 Motor and Motor Circuit Protection • Optimal Branch Circuit Protection (Back-up Overload Protection): • 125% or up of FLA - FRN/FRS • 130% or up of FLA- LPN/LPS • 150% or up of FLA- LPJ • 200% or up of FLA- LP-CC © 2015 Eaton. All Rights Reserved.. 44 1000 FRN-R-1-8/10 Time in Seconds 100 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 45 1000 FRN-R-1-8/10 Time in Seconds 100 Motor Damage Curve 10 1 Overload Relay 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 46 1000 FRN-R-1-8/10 Time in Seconds 100 1 Motor Damage Curve 300 % Overload 0.1 Overload Relay 10 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 47 Single-Phasing • Single phasing is the opening of one phase of a three phase circuit. © 2015 Eaton. All Rights Reserved.. 48 Primary Single Phasing • Primary wire broken by: • Storm - Wind - Ice - Sleet - Hail - Lightning • Vehicle or Plane Striking Pole • Falling Tree Limbs • Construction Mishaps • Primary wire burned out from short-circuit created by animals(i.e. squirrel to ground) © 2015 Eaton. All Rights Reserved.. 49 Primary Single Phasing • Defective contacts on primary breaker - failure to make up on all 3 poles. • Failure of 3 shot automatic reclosers to make up on all 3 poles. • Open pole on 3Ø auto. voltage tap changer • Open winding in one phase of transformer • Primary fuse open © 2015 Eaton. All Rights Reserved.. 50 Primary Single Phasing Normal Condition 1.4 A 1.4 A M 1.4 A 208V 1/3 HP Motor 40 C F.L.A. = 1.4 Amperes © 2015 Eaton. All Rights Reserved.. 51 Primary Single Phasing Single Phase Condition Assume one phase lost on the primary side of transformer. 1.61 A 3.22 A (115%) (230%) 1.61 A 208V 1/3 HP Motor M (115%) 40 C F.L.A. = 1.4 Amperes © 2015 Eaton. All Rights Reserved.. 52 Secondary Single Phasing • Damaged Motor Starter Contact - One Pole Open • Burned open overload relay (heater) • Damaged switch or circuit breaker on the main, feeder, or branch circuit. • Open fuse or open pole in breaker on main, feeder, or branch circuit. • Open cable or bus on secondary of transformer terminals © 2015 Eaton. All Rights Reserved.. 53 Secondary Single Phasing • Open cable caused by overheated lug on secondary side-connection to service head. • Open connection in wiring such as in motor junction box (caused by vibration) or any pull box • Open winding in motor • Open winding in one phase of transformer winding © 2015 Eaton. All Rights Reserved.. 54 Secondary Single Phasing Normal Condition 1.4 A 1.4 A M 1.4 A 208V 1/3 HP Motor 40 C F.L.A. = 1.4 Amperes © 2015 Eaton. All Rights Reserved.. 55 Secondary Single Phasing Single Phase Condition Contacts on one phase are worn out resulting in an open circuit 0A 2.4 A (173%) 2.4 A 208V 1/3 HP Motor M (173%) 40 C F.L.A. = 1.4 Amperes © 2015 Eaton. All Rights Reserved.. 56 1000 FRN-R-1-6/10 Time in Seconds 100 Motor Damage Curve Secondary Single Phasing 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 57 1000 FRN-R-1-8/10 Time in Seconds 100 Motor Damage Curve Secondary Single Phasing Overload Relay 10 1 0.1 0.01 1 10 100 Current in Amperes © 2015 Eaton. All Rights Reserved.. 1000 58 What about short circuit protection for a motor circuit? © 2015 Eaton. All Rights Reserved.. Motor and Motor Circuit Protection Current Source M • Short Circuit Condition © 2015 Eaton. All Rights Reserved.. 60 If the overcurrent protective devices are sized according to the maximums in NEC® 430.52, will the motor circuit components be protected from damage? © 2015 Eaton. All Rights Reserved.. TYPE 1 PROTECTION vs. TYPE 2 PROTECTION © 2015 Eaton. All Rights Reserved.. TYPE 1 vs. TYPE 2 PROTECTION • What is Type 1 and Type 2 Protection? • IEC 947-4-1 Standard • Type 1 Protection(Damage) • UL 508 Listing • Type 2 Protection(No Damage) • Type 2 Tables from Manufacturer © 2015 Eaton. All Rights Reserved.. 63 TYPE 1 vs. TYPE 2 PROTECTION • Type 1 Protection: • “Requires that, under short-circuit conditions, the contactor or starter shall cause no danger to persons or installation and may not be suitable for further service without repair and replacement of parts.” • Similar to UL 508 requirements © 2015 Eaton. All Rights Reserved.. 64 TYPE 1 vs. TYPE 2 PROTECTION • Type 2 Protection: • “Requires that, under short-circuit conditions, the contactor or starter shall cause no danger to persons or installation and shall be suitable for further use. The risk of contact welding is recognized, in which case the manufacturer shall indicate the measure to be taken as regards the maintenance of the equipment.” © 2015 Eaton. All Rights Reserved.. 65 Type 2 Protection Tables © 2015 Eaton. All Rights Reserved.. 66 TYPE 1 vs. TYPE 2 PROTECTION • Does NEC® require Type 2 protection? © 2015 Eaton. All Rights Reserved.. 67 TYPE 1 vs. TYPE 2 PROTECTION • NEC® section 110.10: Circuit Impedance, ShortCircuit Current Ratings, and Other Characteristics. The overcurrent protective devices, the total impedance, the equipment short-circuit current ratings, and other characteristics of the circuit to be protected shall be selected and coordinated to permit the circuitprotective devices used to clear a fault to do so without extensive damage to the electrical equipment of the circuit……Listed equipment applied in accordance with their listing shall be considered to meet the requirements of this section. © 2015 Eaton. All Rights Reserved.. 68 TYPE 2 PROTECTION • Why Is Total Protection Important? • Maximum Safety To Personnel And Equipment • Minimum Cost To Stay In Service • Maximum Productivity From The Equipment © 2015 Eaton. All Rights Reserved.. 69 Motor and Motor Circuit Protection • Overload Protection • Overload Relay • Fuses for Backup • Short Circuit Protection • Fuse, Circuit Breaker, MCP • Type 2 Protection(No Damage) © 2015 Eaton. All Rights Reserved.. 70 © 2015 Eaton. All Rights Reserved.. 71