Three-phase Asymmetry and Phase-sequence Phase-loss Relay K8AB-PA CSM_K8AB-PA_DS_E_2_1 Ideal for 3-phase voltage asymmetry monitoring for industrial facilities and equipment. • Monitor voltage asymmetry, phase sequence, and phase loss for three-phase 3-wire or 4-wire power supplies with just one Unit. Switch setting for 3-phase 3-wire or 3-phase 4-wire power supply. • One SPDT output relay, 6 A at 250 VAC (resistive load). • World-wide power specifications supported by one Unit (switchable). • Relay status can be monitored using LED indicator. Refer to Safety Precautions for the K8AB Series. Refer to page 9 for the Q&A section. Model Number Structure ■ Model Number Legend K8AB-@@ 1 2 3 1. Basic Model K8AB: Measuring and Monitoring Relays 2. Functions PA: Three-phase Asymmetry and Phase-sequence Phase-loss Relay. 3. Rated Input Voltage 1: AC 115, 127, 133, 138, 200, 220, 230, 240 2: AC 220, 230, 240, 277, 380, 400, 415, 480 1 K8AB-PA Ordering Information ■ List of Models Three-phase Asymmetry and Phase-sequence Phase-loss Relay Rated input (See note 2.) 3-phase 3-wire mode AC 200, 220, 230, 240 3-phase 4-wire mode AC 115, 127, 133, 138 3-phase 3-wire mode AC 380, 400, 415, 480 3-phase 4-wire mode AC 220, 230, 240, 277 Model K8AB-PA1 K8AB-PA2 Note: 1. Three-phase, three-wire or four-wire and the input range are switched using a DIP switch. 2. The power supply voltage is the same as the rated input voltage. 2 K8AB-PA Ratings and Specifications ■ Ratings Rated input voltage K8AB-PA1 Three-phase, three-wire Mode: 200, 220, 230 and 240 VAC Three-phase, four-wire Mode: 115, 127, 133 and 138 VAC K8AB-PA2 Three-phase, three-wire Mode: 380, 400, 415 and 480 VAC Three-phase, four-wire Mode: 220, 230, 240 and 277 VAC Input load K8AB-PA1: 25 VA max. K8AB-PA2: 45 VA max. Operating value setting range (ASY.) Asymmetry rate: 2% to 22% Operating value Asymmetry operating value = Rated input voltage × Asymmetry set value (%) The asymmetry operation will function when the potential difference between the highest and lowest voltage phases equals or exceeds the asymmetry operating value. Reset value setting range (HYS.) 5% to 50% of operating value Reset method Automatic reset Operating time setting range (T) Asymmetry 0.1 to 30 s Reversed phase/phase loss 0.1 s max. Startup lock time (LOCK) 1 s or 5 s (Switched using DIP switch.) Indicators Power (PWR): Green, Relay output (RY): Yellow, Alarm outputs (ALM): Red Output relays One SPDT relay (NC operation) Output relay ratings Rated load Resistive load 6 A at 250 VAC (cosφ = 1) 6 A at 30 VDC (L/R = 0 ms) Inductive load 1 A at 250 VAC (cosφ = 0.4) 1 A at 30 VDC (L/R = 7 ms) Maximum contact voltage: 250 VAC Maximum contact current: 6 A AC Maximum switching capacity: 1,500 VA Minimum load: 10 mA at 5 VDC Mechanical life: 10,000,000 operations Electrical life: Make: 50,000 times, Break: 30,000 times Ambient operating temperature −20 to 60°C (with no condensation or icing) Storage temperature −40 to 70°C (with no condensation or icing) Ambient operating humidity 25% to 85% (with no condensation) Storage humidity 25% to 85% (with no condensation) Altitude 2,000 m max. Terminal screw tightening torque 0.49 N·m Terminal wiring method Recommended wire Solid wire: 2.5 mm2 Twisted wires: AWG16, AWG18 Note: 1. Ferrules with insulating sleeves must be used with twisted wires. 2. Two wires can be twisted together. Recommended ferrules Al 1,5-8BK (for AWG16) manufactured by Phoenix Contact Al 1-8RD (for AWG18) manufactured by Phoenix Contact Al 0,75-8GY (for AWG18) manufactured by Phoenix Contact Case color Munsell 5Y8/1 Case material ABS resin (self-extinguishing resin) UL94-V0 Weight Approx. 120 g Mounting Mounted to DIN Track or via M4 screws (tightening torque: 1.2 N·m) Dimensions 22.5 (W) × 90 (H) × 100 (D) mm 3 K8AB-PA ■ Specifications Input frequency range 45 to 65 Hz Overload capacity Continuous input: 115% of maximum input, 10 s max.: 125% of maximum input Setting error Operating value Set value ±10% full scale Operating time Repeat error Startup lock time Set value ±0.5 s Operating value Operating value ±2% Error calculation: Error = ((Maximum operating value − Minimum operating value (over 10 operations))/2)/ Average value × 100% Reset value Operating value × 95% ±2% Error calculation: Error = ((Maximum reset value − Minimum reset value (over 10 resets))/2)/Average value × 100% Operating time Operating time repeat error: ±50 ms Asymmetry: Measured when the input suddenly changes from the three-phase asymmetry status to a difference between the maximum and minimum phases of 120% of the asymmetry operating value. Startup lock time Startup lock time repeat error: ±0.5 s (The operating time when the operating time is set to the minimum value and the power supply suddenly changes from 0% to 100%.) Temperature influence Operating value Drift based on measured value at standard temperature: −20°C to standard temperature: ±1,000 ppm/°C max. Standard temperature to 60°C: ±1,000 ppm/°C max. (Humidity: 25% to 80%) Operating time Fluctuation based on measured value at standard temperature: −20°C to standard temperature: ±10% max. Standard temperature to 60°C: ±10% max. (Humidity: 25% to 80%) Humidity influence Operating value Based on ambient humidity of 65% 25% to 80%: ±5% max. Operating time Based on ambient room humidity 25% to 80%: ±10% max. Influence of input frequency At 45 to 65 Hz Operating value ±5% max. Operating time ±10% max. Note: The error in the operating value and operating time under standard conditions. Applicable standards Conforming standards EN60255-5 and EN60255-6 Installation environment (Pollution Degree 2, Overvoltage Category III) EMC EN61326 Safety standards UL508 Insulation resistance 20 MΩ min. Between external terminals and case Between input terminals and output terminals Dielectric strength 2,000 VAC for one minute Between external terminals and case Between input terminals and output terminals Noise immunity 1,500 V power supply terminal common/normal mode Square-wave noise of ±1 µs/100 ns pulse width with 1-ns rise time Vibration resistance Frequency 10 to 55 Hz, 0.35-mm single amplitude, acceleration 50 m/s2 10 sweeps of 5 min each in X, Y, and Z directions Shock resistance 100 m/s2, 3 times each in 6 directions along three axes (up/down, left/right, forward/backward) Degree of protection Terminal section: Finger protection 4 K8AB-PA Connections ■ Wiring Diagram Voltage Asymmetry and Phase Sequence/Phase Loss Operation Diagram L1 N L1 L2 L3 Asymmetry operation voltage (set value) Input L2 L3 Voltage input Flashing Lit Alarm indicator L1 N L2 L3 Relay T T: Operating time (0.1 to 30 s) 14 Signal output 12 T1: Power ON lock (1 s or 5 s) T1 Phase loss operation Phase sequence operation L1 L3 L1 11 Relay signal output L1 L3 L2 L2 L2 L1 L3 Input L2 Load L3 Flashing Flashing Alarm indicator Operation Indicators Relay Note: 1. K8AB-PA output relay is normally operative. 2. The power ON lock prevents unnecessary alarms from being generated during the instable period when the power is first turned on. There is no relay output during timer operation. 3. Phase loss is detected by L1, L2, and L3 voltage drops. A phase loss will exist if any of the phases drops below 60% of the rated input. 4. L1 and L2 function both as the power supply terminals and as input terminals. If the voltage drops dramatically, then the Relay will not operate due to an undervoltage. 5. Motor load phase loss cannot be detected during operation. 6. Phase loss is detected based on voltage, so phase loss cannot be detected on the load side. Calculating the Asymmetry Operating Voltage Asymmetry operation condition = (Highest voltage − Lowest voltage) > Asymmetry operating voltage Asymmetry operating voltage = Rated input voltage (V) × Asymmetry set value (%) Note: The rated input voltage is selected and set with the DIP switch. Item Display Ry_LED Contact operation Alarm_LED Alarm_LED Asymmetry OFF ON OFF Phase loss OFF ON OFF Reversed phase OFF Flashing (See note.) OFF Correct phase ON OFF ON Note: The indicator will flash once per second after a phase loss is detected and once per 0.5 second during the detection time. 5 K8AB-PA Nomenclature ■ Front Indicators Item Meaning Power indicator (PWR: Green) Terminal block (See notes 1 and 2.) Lit when power is being supplied (see note). Relay status indicator Lit when relay is operating (normally lit). (RY: Yellow) Asymmetry rate knob (ASY.) Alarm indicator (ALM: Red) Asymmetry voltage error indicator The indicator flashes to indicate the error status after the input has exceeded the threshold value while the operating time is being clocked. Power indicator Relay status indicator Alarm indicator Operating time knob (T) Note: The input across L1 and L2 is used for the internal power supply. Therefore, the power indicator will not be lit if there is no input across L1 and L2. Setting Knobs Item Terminal block (See notes 1 and 2.) Usage Asymmetry rate knob (ASY.) Used to set the asymmetry rate to 2% to 22%. Operating time knob (T) Used to set the operating time to 0.1 to 30 s. Note: 1. Use either a solid wire of 2.5 mm2 maximum or a ferrule with insulating sleeve for the terminal connection. The length of the exposed current-carrying part inserted into the terminal must be 8 mm or less to maintain dielectric strength after connection. For 2.5 mm2 or smaller solid wires 8 mm max. For ferrules with insulating sleeves 8 mm max. Recommended ferrules Phoenix Contact • Al 1,5-8BK (for AWG16) • Al 1-8RD (for AWG18) • Al 0,75-8GY (for AWG18) 2. Tightening torque Recommended: 0.49 N·m Maximum: 0.54 N·m 6 K8AB-PA ■ Operation and Setting Methods Connections 1. Input Connect to L1, L2, and L3 (for three-phase three-wire mode) or L1, L2, L3, and N (for three-phase fourwire mode), depending on the mode selected using pin 2 on the DIP switch. The Unit will not operate correctly if the DIP switch setting and the wiring do not agree. Make sure the phase sequence is wired correctly. The Unit will not operate normally if the phase sequence is incorrect. 2. Outputs Terminals 11, 12, and 14 are output terminals for SPDT. N L1 L2 L3 Voltage input L1 L2 N L3 14 Signal output 12 11 Relay signal output Load DIP Switch Settings The power ON lock time, number of wires, and rated voltage are set using the DIP switch located on the bottom of the Unit. DIP Switch Functions ON K8AB-PA1 SWITCH OFF SW1 SW2 SW3 SW4 DIP switch ON ● ↑ 4 3 2 1 ON Power ON lock time 5s OFF ❍ ↓ OFF --- --- --- ● 1s --- --- --- ❍ Number of wires Three-phase, four-wire --- --- ● --- Three-phase, three-wire --- --- ❍ --- Rated voltage Three-phase, Three-phase, three-wire four-wire 240 V 138 V ● ● --- --- 230 V 133 V ● ❍ --- --- 220 V 127 V ❍ ● --- --- 200 V 115 V ❍ --- --- --- 3 2 1 Note: All pins are set to OFF at the factory. K8AB-PA2 SWITCH ON ● ↑ 4 ON Power ON lock time 5s OFF ❍ ↓ OFF --- --- --- ● 1s --- --- --- ❍ Number of wires Three-phase, four-wire --- --- ● --- Three-phase, three-wire --- --- ❍ --- Rated voltage Three-phase, Three-phase, three-wire four-wire 480 V 277 V ● ● --- --- 415 V 240 V ● ❍ --- --- 400 V 230 V ❍ ● --- --- 380 V 220 V ❍ ❍ --- --- Note: All pins are set to OFF at the factory. 7 K8AB-PA Setting Method 1. Asymmetry Asymmetry is set using the asymmetry operation knob (ASY.) The setting can be between 2% and 22% of the rated input. Turn the knob while there is an input to the input terminals until the alarm indicator flashes (when the set value and the input have reached the same level.) Use this as a guide to set the asymmetry. The rated input depends on the model and DIP switch setting. Example: K8AB-PA1 with Pin 2 Turned OFF (Three-phase, Three-wire Mode) and Pins 3 and 4 Turned OFF (Rated Voltage of 200 V) The rated input voltage is 200 VAC and the setting range is 4 to 44 V. If the setting (ASY. knob) is at 10%, the asymmetry operation voltage is 20 V and an alarm will be output if the difference between the minimum and maximum phases for two of the three phases exceeds 20 V. 2. Operating Time The operating time is set using the operating time knob (T). The operating time can be set to between 0.1 and 30 s. Turn the knob while there is an input to the input terminals until the alarm indicator flashes (when the set value and the input have reached the same level.) Use this as a guide to set the operating time. If the input exceeds the asymmetry set value, the alarm indicator will start flashing for the set period and then stay lit. Dimensions (Unit: mm) Three-phase Asymmetry and Phase-sequence Phase-loss Relay K8AB-PA1 K8AB-PA2 22.5 100 5 90 72 5 8 K8AB-PA Questions and Answers Q Q Checking Operation How to Measure the Operating Time Asymmetry Change the input rapidly from a symmetric state to an asymmetric state and measure the time until the relay operates. Operating Time Adjust the slide resistor so that the voltage difference applied to the K8AB terminals is equal to or greater than the asymmetry operating value when the auxiliary relay operates, as shown in connection diagram 2. Close the switch and use the cycle counter to measure the operating time. With the rated input voltage applied, gradually change the voltage to any one phase. The Unit will operate when the difference between the maximum and minimum voltage phases reaches or exceeds the asymmetry operating value. Asymmetry operating value = Rated input voltage × Asymmetry set value (%) Example: For monitoring mode set to three-phase three-wire monitoring, a rated voltage of 200 V, and an operating time of 5 s. Note: K8AB-PA@ output relays are normally operative. L1 Asymmetry operating voltage (set value) Inputs L2 L3 Connection Diagram 2 L1 Flashing Lit Alarm indicator V1 3φ 200 VAC L2 L1 R1 Contact T T: Operating time (0.1 to 30 s) T1: Startup lock time (1 s or 5 s) X/b X X/a V2 V3 L3 R2 L2 R1: Slide resistor 200 Ω 200 W R2: 100 Ω 400 W Connection Diagram 1 L3 L1 V1 3φ 200 VAC L2 V2 V3 ± L1 0 to 150 V C 200 V Cycle counter L2 L3 Three-phase variable autotransformer Q Checking the Phase Sequence and Phase Loss Operation Phase Sequence Operation Switch the wiring, as shown by the dotted lines in connection diagram 1, to reverse the phase sequence and check that the K8AB operates. Phase Loss Operation Create a phase loss for any input phase and check that the K8AB operates. Q Operating Adjustment Knobs Use a screwdriver to turn the knobs. There is a stopper to prevent the knob from turning any further once it has been turned completely to the left or right. Do not force the knob past these limits. Q Load-side Phase Loss In principle, phase loss cannot be detected on the load side because the K8AB-PA@ measures three-phase voltage to determine phase loss. 9 K8AB-PA Q Motor Load Phase Loss during Operation Phase loss cannot be detected for motor loads during operation. Use the asymmetry detection function. Normally, three-phase motors will continue to rotate even if one phase is open. The three-phase voltage will be induced at the motor terminals. The diagram shows voltage induction at the motor terminals when phase R is lost with a load applied to a three-phase motor. The horizontal axis shows the motor load as a percentage of the rated load, and the vertical axis shows voltage as a percentage of the rated voltage. The lines in the graph show the voltage induced at the motor terminals for each load when phase loss occurs during operation. As the graph shows, phase loss cannot be detected because the motor terminal voltage does not drop very much even if a phase is lost when the load on the motor is light. Use the asymmetry detection function to detect asymmetry in the motor terminal voltages. Set the operating time carefully because it will affect the time from when the phase loss occurs until tripping when this function is used. Characteristic Curve Diagram Voltage (as a percentage of rated voltage) Note: This characteristic curve shows the approximate values only. 100 95 90 VST 85 80 VTR 75 70 65 60 55 50 45 0 VRS 10 20 30 40 50 60 70 80 90 100 110 Motor load (as a percentage of rated load) Note: For phase loss of phase R. VST, VTR, and VRS indicate the motor terminal voltage at phase loss. ALL DIMENSIONS SHOWN ARE IN MILLIMETERS. To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527. In the interest of product improvement, specifications are subject to change without notice. 10 Read and Understand This Catalog Please read and understand this catalog before purchasing the products. Please consult your OMRON representative if you have any questions or comments. Warranty and Limitations of Liability WARRANTY OMRON's exclusive warranty is that the products are free from defects in materials and workmanship for a period of one year (or other period if specified) from date of sale by OMRON. OMRON MAKES NO WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, REGARDING NON-INFRINGEMENT, MERCHANTABILITY, OR FITNESS FOR PARTICULAR PURPOSE OF THE PRODUCTS. ANY BUYER OR USER ACKNOWLEDGES THAT THE BUYER OR USER ALONE HAS DETERMINED THAT THE PRODUCTS WILL SUITABLY MEET THE REQUIREMENTS OF THEIR INTENDED USE. OMRON DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED. 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PERFORMANCE DATA Performance data given in this catalog is provided as a guide for the user in determining suitability and does not constitute a warranty. It may represent the result of OMRON’s test conditions, and the users must correlate it to actual application requirements. Actual performance is subject to the OMRON Warranty and Limitations of Liability. ERRORS AND OMISSIONS The information in this document has been carefully checked and is believed to be accurate; however, no responsibility is assumed for clerical, typographical, or proofreading errors, or omissions. 2008.12 In the interest of product improvement, specifications are subject to change without notice. OMRON Corporation Industrial Automation Company http://www.ia.omron.com/ (c)Copyright OMRON Corporation 2008 All Right Reserved.