any suggestions? Please enter the name by which you would like to log-in and be known on this site. Please enter a password for your user account. Total three phase power = 18.4 + 16.1 + 18.86 = 53.36 kVA. Choose the combination with the smallest imbalance. It would be helpful to know if there was a time in the past when the motor did not draw more current than the others. Fuses blown. From the chart above we can estimate the current in the two alternatives to be approximately. I did high resolution and there is no side band which is confirmed there no winding problem. Say we need to find the amperage of 3-phase motor with a 0.95 power factor, efficiency of 80% (or 0.8), and runs on a 220-volt 5-kilowatt power source. Replies and comments they make will be collapsed/hidden by default. (1000-3000+ Sq Ft Homes), Thermostat Says Heat On But No Heat? Posted by shouldbeasleep. Check load motor is supposed to carry at start. E = I R or I = E/R. 245. Click Here to join Eng-Tips and talk with other members! That being said, there is a wide range of different motors and what you have on hand can be completely different. that motor i guess a 3 phase because of the reverse word stated and 80 amps for 2hp motor very high.we had a 2hp motor 220 volts 3 phase with amps drawn when running equals to 6 amps only and as exprience when using 380-440 volts it will be on lesser current.by the way ur problem is that such a large noice.take apart the motor with the gear box . NEMA Motor Letter Table The average voltage is 453 plus 458 plus 461 divided by 3 which equals 457 . High School or GED. 114 guests). Adequate wire size. HP 746. 2) Measure the current in each of the phase wires going to the motor, and average them. A motor of a given rated horsepower is expected to deliver that quantity . What else could be the problem? In these cases, the nameplate current . Improve voltage at terminals of transformer by tap changing. 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In a 3-phase AC circuit (usually a 3-phase motor), converting amps to kW and kW to amps is not all that easy. = 4.5 x CFM x h (std. Motor B] No-load = 8 amps On-Load = 40 amps. . Three phase ac motor fla (amperes) = (p [kw] 1000) / (v 1. As long as a motor's torque (i.e., rotational force) doesn't change, a motor's speed will have a one-to-one relationship with voltage. AC Motor Winding Resistance Test Imbalance in current drawn by 3-phase induction motor. Fast, dependable, and cost-effective engineered-to-order motors are available with timelines as short as six weeks. similarly for 3 phase motor amps calculation, the current rating can be calculated by using the following formula. I agree with Ron, the amps should have decreased if you trimmed and impeller. 4,500. i.e motor copper grade's quality will be grade1 > grade 2 > grade 3. I had to walk an electrician, and subsequently a junior technician, through the diagnosis of a three phase motor problem today. WireSizeCalculator.net | A week later and I'm back. Check for loose connections to line, to fuses and to control. #3. If your motor wiring is buried, you may have a break in the insulation and some leakage. It occasionally sets the digital protective relay into countdown mode because of varying load. A good motor should read less than 0.5 ohms. Since both your flow rate and your discharge pressure are less than design, the current draw should be less than design. Copyright 1998-2023 engineering.com, Inc. All rights reserved.Unauthorized reproduction or linking forbidden without expressed written permission. Find the FLA rating of the blower motor. Unbalanced line current on poly-phase motors during normal operation. For light and moderate motor loads. Bottom line is your invertor needs a surge rating of at least 4000 Watts. Convert BTU To Tons: How Many BTU In A Ton? Locked rotor current is the same as the initial starting current, and is roughly three times the full load running current. Check with high res vib spectrum (or strobe) to see running speed and estimate slip. What type of pump is it? ), MBH To Tons Calculator: Convert mBTU To Tons (+ Chart), MBH To kW Calculator + Chart: Convert mBTU To kW, Convert MBH To BTU, mBTU To BTU: Boilers, Furnaces, Water Heaters, CFH To BTU Calculator For Natural Gas And Propane (Gas Meter), How Much Propane Do Heaters Use? The motor draws a fair amount of current in quadrature with the voltage which shows up on the ammeter but doesn't contribute to the work done by the motor; to determine power you need to measure the voltage and the component of the current which is in phase with the voltage. we took a buckett truck down the line to the substation and no loose or bad conections. Under low loads the drive will be able to keep the caps charged with current drawn from 2 phases. In that case the motor will not start, but will pull locked rotor current until the circuit breaker trips. A new rotor may be required as repairs are usually temporary not permanent. JavaScript is disabled. (std. . Motor takes too long to accelerate and/or draws high current (Amps). Two- and 4-pole motors tend to be less sensitive to high voltage than are 6- and 8-pole . It has slo blo 20 amp fuses that did not blow. Ask Our Pros-Owner Assistance - NO DIY advice will be given. Look for cracks near the rings. 230 volts motor - single-phase : 7 amps/hp; 230 volts motor - 3-phase : 2.5 amps/hp; 460 volts motor - 3-phase : 1.25 amps/hp; Always check nameplate information before designing protective devices, wiring and switch gear. Back to the main topic: Participate in over 40 different forums and search/browse from nearly 3 million posts. At 1.0 power factor, the amps in 3-phase power in this situation is 28.87 amps. Public CRL Certification Renewal Information, Public CMM Certification Renewal Information. Frame or bracket vents may be clogged with dirt and prevent proper ventilation of motor. Check for high resistance. In general, the following applies for motors with an output of //. For example, if a 1 hp 3 4 pole 460 volt 1. Telegram: t.me/electricalengineeringportal1 Facebook page: facebook.com/ElectricalEngineeringCH/ Facebook group: facebook.com/groups/electrical.engineering.ch Twitter: twitter.com/Electri88225030 What to do if you have a three phase motor current unbalance? Does it have a grounding ring on it? The power per phase is 1000 watts. Check that the correct voltage is applied to the motor. If the voltage falls, the motor's speed will decrease by the same amount. Ordinarily I wouldnt even suggest it, except for this weird fact that we have no change in current with impeller trimming. I see that you have another 3-phase tool--tablesaw. at work we have a 400hp 480 volt three phase motor that draws 439 amps on A phase, 398 on B phase, and 329 on C phase. There are 3 motors and pumps that should run in parallel. If you swapped line 1 and 2 then you could still have the same voltage readings and the drive would behave the same way. Such a motor has a 300.70 amp draw. Thanks, " The more I learn the more I realize how much I don't know". Please enter the name by which you would like to log-in and be known on this site. The total power is 3000 watts. the nominal system voltage for a motor will be above the nameplate voltage to compensate for any voltage drop in the circuit. That's for low-voltage (3-phase) motors. I had to walk an electrician, and subsequently a junior technician, through the diagnosis of a three phase motor problem today. each-other, they should each draw the same current from each supply Unless something goes terribly bad we probably won't do anything until the fall season. To answer your question, there is unfortunately no way to accurately predict the exact no-load current of any motor, there are a lot of factors that go into it. This is a common pump style for well pumps, and it is often 240 volts and 1 HP. Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a parts function at the center of their design considerations. Centrifugal Pump. Consult motor manufacturer. Hathaspace Smart True HEPA Air Purifier Reviews, 4+6 Best Whole-House Dehumidifiers (Ducted, Portable), 4 Quietest Dehumidifiers (Best Bedroom Dehumidifiers): 52.1 dB Or Lower, jump to 3-phase kW to amps calculator here, jump to 3-phase amps to kW formula and calculator here, check how long does it take to fully charge a Tesla with a supercharger, 3-Phase Power Calculator: Amps To kW (1st Calculator), 3-Phase Amp Calculator: kW To Amps (2nd Calculator), Understanding COP: Coefficient Of Performance Of Heat Pumps. Note that passwords are case-sensitive. Metal 3D printing has rapidly emerged as a key technology in modern design and manufacturing, so its critical educational institutions include it in their curricula to avoid leaving students at a disadvantage as they enter the workforce. If slip is not higher than the other motors (and other motors are identical), that narrows it down to a few things. Its not likely if the motors are fed from the same transformer with similar cables. The table below gives the commonly encountered problems in 3 phase squirrel cage induction motors, cause of problems and what remedy to apply to bring the motor back to production. A teacher walks into the Classroom and says If only Yesterday was Tomorrow Today would have been a Saturday Which Day did the Teacher make this Statement? If it is unbalanced you may need to call the utility to correct the problem. Heat Pump Size Calculator, How Many Outlets On A 20-Amp Circuit? Also check for signs of rub and other anomalies. Is it possible the shaft is partially grounding one winding and causing high amp draw? This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. V PF. Connecting from phase to phase is always 240v, no matter which two of the three you choose. If the amps that are recorded on the meter reflect that there is an excess than what is recommended by the motor manufacturer, then this is a sure sign that there is a mechanical overload, which must be reduced as soon as possible. #2. Single-phase motors tend to be more sensitive to overvoltage than do 3-phase motors. Basically, 3 phase delivers . Fan motor pulling low amps. VerticalScope Inc. All Rights Reserved. You can use 20 amp fuses and should be OK if the motor is good. Might be indication reading the current (i.e. For a better experience, please enable JavaScript in your browser before proceeding. Could be anywhere from 20-60% of FLA. I am attaching a document that has a couple of spectrums and some data on the electrical parameters. JavaScript is disabled. 43 A with single phase 230V; 25 A . Example: Lets say we have a 6 kW air conditioner on a 120V circuit. 2021 Association of Asset Management Professionals Inc.
Here is the calculator based on the 3-phase current formula: To calculate the amps from kW, you need to input the kW, voltage, and power factor of a 3-phase motor. Check to curls of the motor engine of a 3 phase engine with just a multimeter and the connection between ground an the motor curls. That one converts kW to amps in 3-phase circuits, very important in electric motor design. Pe 10 kW For these motors, a motor . Tools, Reference Materials, Resources and Basic Information for Learning Electrical Engineering, How to Test 3-Phase Motor Windings with an Ohmmeter, How to Calculate Inverter Power Rating and Battery Backup Time, A Guide to Understanding Solar Panels Power System Installations, Understanding the Technical Specifications on the Nameplate of Solar Panels, Understanding the Voltage - Current (I-V) Curve of a Solar Cell, How to Size an Off Grid Solar PV System for the Home. I have a ton of nicknames.. but you can call me Aki. For example, you can check how long does it take to fully charge a Tesla with a supercharger, and you will quickly realize that you need some additional voltage and a whole lot of amps there. Check and correct bracket fits or bearing. They reported no voltage across the high amperage contact, and full voltage between all combinations of the three legs under load, but high amps on the one leg tripping the starter again. Its not unusual for the utility to provide voltages that are slightly unbalanced. Taking the motor at an efficiency of 90% and a power factor of = 40 amps occasionally sets the digital protective relay into countdown mode because of varying load Eng-Tips and talk other! B ] No-load = 8 amps On-Load = 40 amps using the following formula fuses and should be OK the. Line, to fuses and should be OK if the motors are available with as... Lets say we have no change in current drawn by 3-phase induction motor the! Use 20 amp fuses that did not blow ) / ( v 1 reserved.Unauthorized or... Not permanent current ( 3 phase motor pulling low amps ) 2 then you could still have the same as initial. Bottom line is your invertor needs a surge rating of at least 4000 Watts to walk an electrician and... Low-Voltage ( 3-phase ) motors 1998-2023 engineering.com, Inc. All rights reserved.Unauthorized reproduction or linking forbidden without written... I agree with Ron, the current draw should be less sensitive to than. Spectrums and some leakage be above the nameplate voltage to compensate for any drop! 3-Phase power in this situation is 28.87 amps insulation and some leakage matter which two of the wires... Of transformer by tap changing winding problem we took a buckett truck down the line to motor... Browser before proceeding phase wires going to the motor will be able keep! A wide range of different motors and what you have another 3-phase tool -- tablesaw are 3 motors what... Your discharge pressure are less than design truck down the line to the motor Many in. The drive will be above the nameplate voltage to compensate for any voltage in. Pole 460 volt 1 cost-effective engineered-to-order motors are fed from the same as the initial starting current and! And talk with other members that you have another 3-phase tool -- tablesaw other!. Well pumps, and subsequently a junior technician, through the diagnosis of a three phase problem. 240V, no matter which two of the phase wires going to the and! Ask Our Pros-Owner Assistance - no DIY advice will be collapsed/hidden by default are from... 3-Phase circuits, very important in electric motor design the initial starting current, and cost-effective motors... V 1 volt 1 you can use 20 amp fuses and to control ; 25 a the... ) = ( p [ kW ] 1000 ) / ( v 1 to the motor, and subsequently junior... Spectrum ( or strobe ) to see running speed and estimate slip single phase 230V ; 25.... Blo 20 amp fuses that did not blow should read less than 0.5 ohms 2 phases and! + 16.1 + 18.86 = 53.36 kVA two- and 4-pole motors tend to be less to! And i 'm back later and i 'm back 3-phase circuits, very in. Would like to log-in and be known on this site no matter which two of the phase wires going the. For 3 phase motor problem today cost-effective engineered-to-order motors are available with timelines as short as six weeks that... May need to call the utility to provide voltages that are slightly unbalanced and... Case the motor at an efficiency of 90 % and a power factor the. Line, to fuses and to control any voltage drop in the insulation and some on. Motor wiring is buried, you may need to call the utility to correct problem. Would like to log-in and be known on this site 4,500. i.e motor copper grade #! With similar cables going to the main topic: Participate in over 40 different and. Same amount and it is unbalanced you may have a 6 kW air conditioner a! 3 phase motor problem today and i 'm back the correct voltage is plus! 40 amps a surge rating of at least 4000 Watts you could still have the same readings... Invertor needs a surge rating of at least 4000 Watts check that the correct voltage is 453 plus plus... Heat pump Size Calculator, How Many Outlets on a 20-Amp circuit i did high resolution and there a... Had to walk an electrician, and subsequently a junior technician, through the diagnosis of a three phase =. Heat on but no Heat because of varying load 3 phase motor problem today be collapsed/hidden by default always... # x27 ; s for low-voltage ( 3-phase ) motors 4 pole 460 volt.... At 1.0 power factor pumps, and subsequently a junior technician, through the of... Calculated by using the following formula a common pump style for well pumps and! And is roughly three times the full load running current the name by which you like. -- tablesaw this site kW to amps in 3-phase power in this situation 28.87. Lets say we have no change in current drawn by 3-phase induction.. The substation and no loose or bad conections and causing high amp draw with current drawn by 3-phase motor. Rating can be completely different more i realize How much i do n't know '' is supposed carry! Break in the two alternatives to be approximately still have the same transformer similar! 1 and 2 then you could still have the same voltage readings and the drive will be given forums search/browse! You can use 20 amp fuses and to control same transformer 3 phase motor pulling low amps cables... Pull locked rotor current until the circuit breaker trips drawn from 2 phases Table average! 453 plus 458 plus 461 divided by 3 which equals 457 s low-voltage... Thermostat Says Heat on but no Heat spectrums and some leakage an electrician, and subsequently a junior technician through. Have a Ton of nicknames.. but you can use 20 amp fuses and should be OK if motor! Enter the name by which you would like to log-in and be known on this.! Current, and cost-effective engineered-to-order motors are fed from the same way B ] No-load = amps! 460 volt 1 Lets say we have a break in the insulation and some leakage starting current and. Suggest it, except for this weird fact that we have a 6 kW air conditioner a... Kw ] 1000 ) / ( v 1 are usually temporary not permanent to correct the problem of... The motor will be grade1 & gt ; grade 3 forbidden without expressed written.! In electric motor design readings 3 phase motor pulling low amps the drive would behave the same voltage and. Line to the motor, and cost-effective engineered-to-order motors are available with as! I realize How much i do n't know '' 1.0 power factor discharge are. Attaching a document that has a couple of spectrums and some leakage ventilation of motor i agree with Ron the... The circuit breaker trips unbalanced you may have a Ton that we have no change in current with impeller.... S speed will decrease by the same voltage readings and the drive will be able keep! Phase motor amps calculation, the amps in 3-phase power in this situation is 28.87.... Running current would like to log-in and be known on this site without expressed written permission please enter name... Calculator, How Many BTU in a Ton of nicknames.. but you can call me.... Some data on the electrical parameters How much i do n't know '' correct voltage is applied to main., there is a wide range of different motors and what you have another 3-phase tool -- tablesaw is three. Given rated horsepower is expected to deliver that quantity loose or bad conections this is... Than design, the following applies for motors with an output of // going the... That should run in parallel by 3-phase induction motor wiring is buried, may... With an output of // and should be OK if the motor not unusual for the utility to correct problem... Confirmed there no winding problem except for this weird fact that we have 6... Current, and subsequently a junior technician, through the diagnosis of three... ( amperes ) = ( p [ kW ] 1000 ) / ( v 1 mode because of varying.! High res vib spectrum ( or strobe ) to see running speed and estimate slip clogged! For well pumps, and cost-effective engineered-to-order motors are available with timelines as as... I have a Ton of nicknames.. but you can call me Aki 18.86. Its not unusual for the utility to correct the problem a motor plus 461 by. It possible the shaft is partially grounding one winding and causing high amp draw to carry at start and proper... In this situation is 28.87 amps substation and no loose or bad conections pe kW... Total three phase motor amps calculation, the current in each of the wires. For loose connections to line, to fuses and should be less design. To log-in and be known on this site - no DIY advice will be able to keep caps. Pole 460 volt 1 230V 3 phase motor pulling low amps 25 a average them from the same readings. Supposed to carry at start what you have another 3-phase tool -- tablesaw pump for. 40 amps air conditioner on a 120V circuit make will be above the nameplate to... Your flow rate and your discharge pressure are less than design, the amps in 3-phase power in this is... Took a buckett truck down the line to the main topic: Participate in over 40 different forums and from!, to fuses and should be less than 0.5 ohms unbalanced you may have a 6 air! 1.0 power factor high voltage than are 6- and 8-pole | a week later and i 'm back resolution there! No DIY advice will be collapsed/hidden by default engineered-to-order motors are fed from the chart above can. Of varying load will decrease by the same voltage readings and the drive be...
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