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Basics of Digital Meters Utility Applications © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 1 of 69 Understanding the basics • Basic Electricity • • • • Safety Analog or Digital Manual or Auto-ranging Displays – Range and Resolution – Icon Symbols – Numerical System • Basic Measurement – DC Volts& AC Volts – Resistance, Capacitance – Current © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 2 of 69 Basic Electricity • Fluid Dynamics – How water flows • Electrical Theory – How electricity flows • Types of Sources – AC vs. DC – Measuring AC © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 3 of 69 Fluid Dynamics to Electrical Theory How water flows • Water Pressure • Voltage (V) – Pressure created by a pump or stored in towers • Flow or Current – The amount of water flowing through a pipe – Pressure applied to the conductor • Amperes or Amp (I or A) – Flow of electrons in the conductor • Impedance – • Impedance or resistance Anything that impedes the () flow of current © 2007 Ideal Industries www.idealindustries.com – Impedes or resist the flow of electrons Basics of Digital Meters- Utility Applications 4 of 69 AC Source • Alternating Current (AC) – Most common – Produced by a generator – Has a positive and negative component © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 5 of 69 DC Source • Direct Current (DC) – Stored energy or derived from AC with electronic rectifier – Positive component only – Used to power electronic devices © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 6 of 69 Understanding the Basics • Basic Electricity • Safety • Analog or Digital • Manual or Auto-ranging • Displays – Range and Resolution – Icon Symbols – Numerical System • Basic Measurement – DC Volts& AC Volts – Resistance, Capacitance – Current © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 7 of 69 Why should we be Concerned? • An electrician troubleshooting a live 480V motor control center receives serious secondand third-degree burns from an electric arc. The cause? – Meter was incorrectly switched to resistance on his multimeter instead of voltage. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 8 of 69 Why should we be Concerned? • Two electricians are severely burned — one fatally — while testing for voltage in a motor starter. One held the multimeter while the other applied the meter's probes to energized terminals. One electrician's movement caused one test lead banana plug (energized from the circuit under test) to pull loose from the multimeter jack. – The plug made contact with the starter's grounded metal enclosure and initiated a high-energy arc. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 9 of 69 Common Mistakes Made • Test Leads in the Current input ports and user mistakenly makes an AC or DC Voltage – In this example there were two errors made by the end user. • AC voltage measurement with the Test leads in the current input. • Improper fuse had been used in the meter from a past error. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 10 of 69 Common Mistakes Made Current If Voltage is measured, Leads in Current input Protection Fuse • Here is what happens. – If the unit is not fused it can lead to damage of meter or to the operator – Current inputs are very low resistance. Most current inputs are less that 1 Ω. This is like applying a short to the line. – For current input protection most DMMs’ are Fused. – The better ones use high energy fusing. Ideal 61-490 series gives a probe error message and High audible warning if this mistake to made © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 11 of 69 Common Mistakes Made • Function Switch in wrong function for attempted measurement – Most common is AC or DC voltage measurement with meter in the Ohms function – Most IDEAL meters are Overload Protected and the protected levels are listed in the operation manual. Ideal 61-700, 61-760 and 61-770 series will give you a Hi-V light and audible warning if you make this Mistake © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 12 of 69 Common Mistakes Made • Using a meter in an area above its stated rating – Example: 2,300 voltage measurement with an instrument rated for Low Voltage (600V AC/DC.) – Overload Protected can not protect you from this Kind of mistake. – Most Overload protected is rated based on instruments highest voltage measurement rating. © 2007 Ideal Industries www.idealindustries.com There are Bold Electricians and Old electricians, but not many Bold-Old ones Basics of Digital Meters- Utility Applications 13 of 69 Common Safety Hazards • Electrical Shock from accidental contact from live electrical circuits or devices – Use double insulated rated leads – Shrouded input jacks with finger guards – Test for proper continuity often. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 14 of 69 Common Safety Hazards • High Voltage transients from lightning, large inductive loads being switched on and off, or capacitive discharge. – Select meter with the proper UL/IEC Category rating for the environment that user is going to be working in. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 15 of 69 Certified Devices and Equipment • Look for tools that are Certificated by an independent lab, – UL , IEC, CSA. • Pay close attention to the safety rating on the equipment. – Never use equipment that is not properly rated, Check Sp IEC Cat ratings • Never use accessories that are not The New UL 61010 standard recommended or rated for your incorporates features of the IEC 601010 standard. This standard has tester or environment. improved safety benefits over the old UL 1244 standard © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 16 of 69 IEC Category Ratings • If a lighting strike was to hit your electrical service a certain amount of energy or impulse would travel and be dissipated by the electrical service. The closer to the source of the impulse the Higher available fault current. • IEC 61010 defines as four Categories: – CAT IV “Origin of installation”, – CAT III Distribution Level, – CAT II Local level, – CAT I Signal Level, © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 17 of 69 Safety Practices • Visually inspect the test tool. – Check for any contaminate on the test leads, tester case, holsters, and accessories. – Never use testers that have signs of cracked cases, or loose components. – Never use a tester in an environment that is beyond the capabilities described in the specifications – Use manufactures recommended replacement components, like leads and fuses. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 18 of 69 Safety Practices • Visually inspect Test Leads – – – – – Proper Category rating Double insulation Shrouded connectors Finger guards Insulation not damaged: not melted, cut, cracked, stretched – Connectors: no insulation pulled away from end connectors – Probe tips: not loose or broken off (too short) © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 19 of 69 Before you get Started • Whenever possible, work on de-energized circuits. • Use well maintained tools and appropriate safety gear • Safety glasses, insulated tools, insulating gloves, flash suits, insulating mats, etc. • Follow proper safety precautions and Lockout /Tag out practices. • Never Work alone when making measurements on live circuits. • Always do a performance test on your tester before making a measurement on an unknown circuit. – Use the 3 point method. Measure a known test point , Make the unknown measurement, then back to the known test measurement. – Change battery when indicated – Check test leads regularly © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 20 of 69 Before you get Started • Quick Check of your Test Tool – – – – • Digital Multimeter or Digital Clamp meter Check the Test Leads Place the DMM in the lowest resistance range and short the Test Leads Move the test lead at in input of the meter at the ankle of the leads. Watch that the resistance is less than 0.5 ohms. Do the same at the leads grip and tips. If at any time during this test the resistance exceeds 0.5 ohms the leads my need to be replaced. It is also a good Idea to check the DC voltage and Ac voltage with a known source before beginning the day. – This doesn't negate the “Three point measurement” method. • • If the unit has current, check the Fuse, and remember to replace with only the manufacturer recommended replacement part. Remember to always be aware of your battery usage. Digital instruments will become erratic or can give improper readings once the power drops below normal operating levels © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 21 of 69 Know your tester • • • • Packaging – Material, • Insulation rating • Environmental rating, Splash proof or not. Features – MIN/MAX, Peak, Hold Measurement Functions – AC Volts, DC Volts Capacitance, etc – Measurement range and Maximum input – Input protection. Safety – CATegory rating, UL, CE © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 22 of 69 Electrical Testers • Analog solenoid Testers – Very low input impedance – AC Voltage – Continuity testing on some models – Low Accuracy and resolution • Digital Testers – – – – Low input impedance AC or DC Voltage Continuity testing Good Accuracy and Resolution • Added Features – NCV (Non-contact Voltage – Current © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 23 of 69 Digital Multimeter and ClampMeter • Multimeter – Full Voltage ranges – Full Resistance ranges – Low current measurement through internal shunts • ClampMeter – One or two Voltage ranges – Limited Resistance ranges – High Current through the fixed jaw (current transformer) The IDEAL TightSight™ ClampMeter is also a Full functional Digital Multimeter © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 24 of 69 Understanding the Testers • Basic Electricity • Safety • Analog or Digital • Manual or Auto-ranging • Displays – Range and Resolution – Icon Symbols – Numerical System • Basic Measurement – DC Volts& AC Volts – Resistance, Capacitance – Current © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 25 of 69 Function Switch • Most DMMs have rotary dial to change test functions. • Manual ranging DMMs – Require manual setting of the range • Lower cost • Forces you to “think” before testing • Faster response time • Auto Ranging DMMs – Automatically chooses the range • Simpler to use © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 26 of 69 Understanding the Testers • • • • Basic Electricity Safety Analog or Digital Manual or Auto-ranging • Displays – Range and Resolution – Icon Symbols – Numerical System • Basic Measurement – DC Volts& AC Volts – Resistance, Capacitance – Current © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 27 of 69 Display Count Typical displays are 2000 or 4000 counts” –Ranges on the dial are in series of 2’s or 4’s –No Function information is displayed. Auto ranging meters will have function symbol – They are also visible on the LCD Display © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 28 of 69 Range and Resolution • Range determines – The maximum reading – The number of decimal places displayed • Resolution determines how many digits after the decimal point – Higher resolution = more decimal places displayed © 2007 Ideal Industries www.idealindustries.com 200V on the 600V Range 1V Resolution 200V on the 400V Range 0.1V Resolution Basics of Digital Meters- Utility Applications 29 of 69 Range and Resolution If we measure a 240V supply with a 2000 count Meter we would be on the 600V range and read 240V © 2007 Ideal Industries www.idealindustries.com Range 600 200 20 2 200m Reading 600 199.9 19.99 1.999 199.9 Basics of Digital Meters- Utility Applications Resolution 1 .1 .01 .001 .1mV 30 of 69 Range and Resolution Measure the same 240V supply with a 4000 count Meter you will be on the 400 Range and have one more digit of resolution 240.0V © 2007 Ideal Industries www.idealindustries.com Range 600 400 40 4 400m Reading 600 399.9 39.99 3.999 399.9 Basics of Digital Meters- Utility Applications Resolution 1 .1 .01 .001 .1mV 31 of 69 Measurement Functions V AC Voltage Measures amount of AC Electrical pressure V DC Voltage Measures amount of DC Electrical pressure mV Milli Volts .001V or 1/1,000 V A Amperes mA Milli Amperes µA Micro Amperes © 2007 Ideal Industries www.idealindustries.com Measures amount of electron flow .001A or 1/1,000 A .000001A or 1/1,000,000A Basics of Digital Meters- Utility Applications 32 of 69 Measurement Functions )))) Ohms Measure of the resistance to electron flow Diode Device used to control direction of electron flow Audible Continuity Audible indication of continuity HZ °F © 2007 Ideal Industries www.idealindustries.com Capacitance Device used to store electrical potential Hertz Measurement of Frequency or number of cycles per/sec Degrees Fahrenheit Temperature Measurement Basics of Digital Meters- Utility Applications 33 of 69 Measuring AC • Average responding meters take a single sample to measure the waveform. – Only accurate where a clean 60Hz sine wave exists • True RMS meters take several sample to improve accuracy of measurement – Found in commercial and industrial environments – Caused by electronic lighting, computers Equipment and Industrial electronic control loads – NEC recommends True RMS meters for testing all electrical power systems © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 34 of 69 Numerical System Term Numerical value Term Numerical value Giga 1,000,000,000 Milli .001 Mega 1,000,000 Micro .000001 kilo 1,000 Nano .000000001 Term giga mega kilo Base milli micro nano Symbols Expressio n G M k m m n 6 3 -3 -6 X10 X10 X10 X10 X10 X10 X10 9 9 0 © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 35 of 69 Understanding the Testers • • • • • Basic Electricity Safety Analog or Digital Manual or Auto-ranging Displays – Range and Resolution – Icon Symbols – Numerical System • Break • Basic Measurement – DC Volts& AC Volts – Resistance, Capacitance – Current © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 36 of 69 Understanding the Testers • • • • • Basic Electricity Safety Analog or Digital Manual or Auto-ranging Displays – Range and Resolution – Icon Symbols – Numerical System • Basic Measurement – DC Volts& AC Volts – Resistance, Capacitance – Current © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 37 of 69 Primary DMM Test Functions • Voltage (V) - measured in volts – Pressure created by a power supply • Current (A) - measured in amps – The amount of electricity flowing through a conductor • Resistance () - measured in ohms – Anything that impedes the flow of current © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 38 of 69 Taking Measurements • • • • • • • • AC Voltage DC Voltage AC Current DC Current Resistance Continuity Capacitance Frequency © 2007 Ideal Industries www.idealindustries.com IDEAL Test Board Basics of Digital Meters- Utility Applications 39 of 69 The Port Panel • Black lead always placed in Common Port (COM) • Red lead is placed in Red Port for the function to be measured • For Voltage connect to the – ( VΩHz) Port © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 40 of 69 DC Voltage Measurement • DC Voltage Measurement • Connect the leads to the VΩHz and COM inputs • Select VDC or – If manual ranging select proper range • For 9V, Select the 20V range • Measure the 9 Volt battery – If connected to the test board look for ( +● Battery● -) test points. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 41 of 69 Parallel Circuit • In a parallel circuit, Voltage is applied equally to each load connected to the circuit – This is how our receptacles in our homes wired.the value Ifare I change of the resistor in this circuit will it change the voltage across the light??? © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 42 of 69 AC Voltage Measurements • AC Voltage Measurement • Connect leads to the VΩHz and COM inputs • Select VAC or – If manual ranging select proper range • For 120V, Select the 200V Range • Measure receptacle, or using test points on a line splitter © 2007 Ideal Industries www.idealindustries.com Never make a Voltage measurement with the leads of the meter in the current input ports Basics of Digital Meters- Utility Applications 43 of 69 Single Phase 3 Wire Meter (Common Residential) Class 100/200 (100/200 Amp) 4 Terminal, 240 Volt © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 44 of 69 Single Phase 3 Wire Meter (Common Residential) Class 100/200 (100/200 Amp) 4 Terminal, 240 Volt © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 45 of 69 Single Phase 3 Wire Meter (Common Residential) Class 100/200 (100/200 Amp) 4 Terminal, 240 Volt © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 46 of 69 Average vs. True RMS • True RMS responding – The Meter calculates the true effective (heating) value of the waveform. – Average sensing meters will not correctly display the effective (heating) value on a “nonsinusoidal waveform. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 47 of 69 True RMS • Measures the area under the sine wave using a root mean square calculation • Gives an accurate AC measurement when harmonics are present • NEC recommends True RMS meters for testing all electrical power systems © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 48 of 69 Current Measurements ClampMeter or Clamp Adapter • AC Current – – – – – Measures the magnetic field around a wire Converts measurement to an amp reading Only a single conductor can be tested Magnetic fields of hot and neutral cancel out Requires a line splitter in power cords • DC Current – DC current is measured using a Hall Effect • An electronic device which measure the EMI of AC and DC current. © 2007 Ideal Industries www.idealindustries.com Test & Measurement Basics of Digital Meters- Utility Applications 49 of 69 AC Current Measurement • AC Current Measurement – Must be made on a single conductor. • Plug hairdryer into line splitter • Plug line splitter into receptacle • Clamp jaws around line splitter • Measure the current draw of the hairdryer © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 50 of 69 Series Current Measurement • In a series circuit, loads within the circuit have an effect on the flow of electricity to the other devices or loads If I increase the value of the resistor will it effect the brightness of light.?? © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 51 of 69 Current Measurements Series Method • Requires an open circuit – electrician must interrupt power – Best to us a meter with fused inputs for safety. • 1 to 10A Max on most DMM’s • Primarily used to measure small Currents © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 52 of 69 DC Current Measurement 4-20mA Control Loop DC current measurement of a 4 to 20mA control loop • A break must be made between the transmitter and Controller. • Place the Test leads in the proper input ports. And select DC mA – 4 mA typically corresponds to zero – 20 mA typically corresponds to Full scale. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 53 of 69 Continuity Measurement • Continuity measurement • Connect the leads to the VΩHz and COM input port • Select the continuity function – Touch leads together © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 54 of 69 “OL” Customer breaker(s) open “Numerical Value” Breaker(s) closed “0.0 to 0.8” SHORT on customer wiring © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 55 of 69 Resistance Measurement • Resistance Measurement • Connect the leads to the VΩHz and COM input port • Select the Ω ohms Function. – If manual ranging select proper range • Measure the Resistor on the Test Board © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 56 of 69 “OL” Customer breaker(s) open “Numerical Value” Breaker(s) closed “0.0 to 0.8” SHORT on customer wiring © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 57 of 69 “OL” Customer breaker(s) open “Numerical Value” Breaker(s) closed “0.0 to 0.8” SHORT on customer wiring © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 58 of 69 Diode Measurement • Diode measurement • Connect the leads to the VΩHz and COM input port • Select the diode function – Place Red lead on + and black lead on – for “Forward bias” © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 59 of 69 Capacitance • Function used in testing capacitors – Storage devices that give motors an initial energy boost • Capacitance is the ability of a capacitor to hold its charge • Measured in microfarads (MFD) © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 60 of 69 Capacitance Measurement • Capacitance Measurement • Connect the leads to the proper input posts – On some units this isn’t the Volt/Ohms port • Select the Capacitance Function , MFD or mF • Measure the capacitor on the PC board © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 61 of 69 Basic Advanced Features • Basic of Advance features found on most high end DMM’s and ClampMeters – Hold or Data Hold – Peak Hold • Peak Min/Max – Min/Max © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 62 of 69 Measurement Functions • Functions button operation – Primary Function MIN/MAX press for 1 Second – Press MIN/MAX To cycle through Max/Min. • Note display © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 63 of 69 Measurement Functions • To exit a Function – Primacy Function • Press for 1 second toggles function A”ON” • Press and hold for 2 seconds toggles function “OFF” – Secondary Function • Press and hold for >2 seconds toggles function “ON” or “OFF” • Note display © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 64 of 69 Hold Measurement Functions • Hold or data hold is used to lock the current measurement reading on the display – While making a measurement, press the Hold button. Remove test leads and observe the displayed reading. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 65 of 69 Measurement Functions • Peak Hold Records the Maximum amplitude of a voltage waveform. • Peak min/max Records the maximum and minimum amplitude of a voltage waveform. Peak = RMS x 1.414 Example: 169.68= 120V x 1.414 © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 66 of 69 Min/Max Measurement Functions • Min/Max Records the minimum and maximum value of a measurement. Each time a new min/max level is achieved the new value will be recorded . – Some DMM will also indicate new recorded values by an audible beep. This Function is not fast enough to capture Power Quality Voltage Event. © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 67 of 69 Voltage Performance Monitor Key Points for comparison • High speed Even capture • Only important events are logged • Events are sorted by Time (log) • Events are sorted by Type (event) • Waveform shape is measured for THD © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 68 of 69 Clamp-On Ground Resistance Test • Advantage is that the ground electrode doesn’t need to be disconnected from the electrical system. • The jaws of the clamp must be placed in the electrical path of the systems grounding wire to the ground rod © 2007 Ideal Industries www.idealindustries.com Basics of Digital Meters- Utility Applications 69 of 69