Individual Motor Calculations

[@rg16315]

What a great Teacher ! Easy to understand and not a boring discussion. Thanks a lot

[@schulerruler]

Thank you for the encouraging words!

[@tgbsuaoanfbeuw]

you do a better job than my teacher at BCIT

[@jeremykoszorek7435]

Your videos are amazing so helpful! I’m currently doing intermediate trade school and I have learned a ton from you videos. Thank you

[@schulerruler]

I'm happy they are helping! Thanks for watching! Good luck.

[@jmcljazz6733]

Hi nice presentation However you are very wrong when you selected the 75 deg column based on rule 28-104. That rule is only for the motor supply conductors using Table 27. Rule 28-104 even says "Motor supply conductors" This is NOT how the size and column of the conductors is selected it is only for the MOTOR SUPPLY CONDUCTORS. In order to select the proper column for the AWG you must and I emphasize must use rule 4-006 (1) or (2). That was a very unfortunate interpretation and completely wrong. I wish you had taught this rule properly now you've miss led every person/apprentice who did not know better. Jim p.s ive taught code for years and this was a huge mistake its NOT done this way at all

[@schulerruler]

To size the conductor between the motor and controller you would do exactly as presented in the video. To size the conductor between the overcurrent and controller you would still use the calculated value from 28-106, but the yes 4-006 would apply and lowest termination or insulation would be your determining ampacity at table 2.

[@jmcljazz6733]

@@schulerruler you never stated motor supply conductors you never referenced 4-006 the most significant rule in the code book you never reference T37 with respect to motor supply conductors Im not criticizing your video Im point out the mistakes and I will leave it at that..Its exactly like this: motor supply conductors are a minimum 1.2 meter long their ampacity is based on the 75 deg column their insulation is based on T37 the distance from the motor is is based on 600 mm or 1.2m for over 100HP 28-104 and T37 there is also ambient temp ie add the difference in ambient to T37 to get the insulation rating 110 deg 125 deg or 200 for that mater Branch conductors 28-106 and 4-006 thats the law period good luck.

[@soheilyazdani9517]

Hi Schuleruler, thank you for all your videos. is it possible to explain table 25 of Ontario electrical safety code? thank you

[@mustafaelleithy3789]

U are using the FLA to calculate the OCPD and the branch circuit ampacity ... I think u should use the FLC ...... Also i have another question ... Passnger elevator( as an example) is considered to be 5 minitues or 15 minutes or 30 or continous rated motors ? In different words ...how can i make the right classification of the intermittent motor I hope u get my guestion

[@hassanmahamat1008]

Hey that's a really great explication helps me lots man thank wish u had a video about the apartment calculation thanks man.

[@mostafaahmed7477]

firstly thanks alot for your fruitful information. secondly i need your help for this problem, if we use Circuit breaker opation at 100% not 80% and i want to size CB for motor i will follw the same rule x2.5flc or what ???

[@Taidenw]

Taking 3rd year in Sask right now online because of Covid-19 and the instructor isn't much help. Thanks for this!

[@schulerruler]

Happy to hear it's helping!

[@abouzarfallah7012]

How calculate cable and overcurrent if 3 20A motor star simultaeously?

[@HariHari-jr5pg]

PLEASE TELL ME THE REFERENCE BOOK ABOUT THE SIZING OF SPARES TO CONTROL PANELSWITH CAL CUTIONS.

[@afkcpu7762]

so if you have a 460 3ph system hooked up to a 10hp motor you would have a 14 fla, 16.1 amp OL, 30 amp circuit breaker. but apparently according to t2@75degree i can use #14?what about 14-104 2). does that override it? if so could you briefly elaborate?. seems goofy having a #14 wire thats can still handle the 1.25multiplier of the FLA which is 17.5. very confusing. doesnt seem right that the OL is a bit higher than the conductor even tho i understand that the conductor wont necessarily burn/melt, but doesnt seem right. thanks for these.

[@Blue_collar_fitness]

This was a short but very well put video thank you

[@schulerruler]

Thank you!

[@flyeagles3437]

Hey thanks for the vid. Do the calculations change if it is a 120v 1 ph motor? thanks

[@schulerruler]

For single phase if not given the FLA we are permitted to use table 45 to obtain the FLA, but still use any given FLA over tables. Otherwise, same process.

[@flyeagles3437]

@@schulerruler appreciate the response

[@Honhjun365]

Is table D16 used for CB?

[@paulsidhu889]

thank you so much sir, you explained it so well and it helped me out alot

[@brimmedHat]

Hey! Thanks for the great content. When calculating the bond size with table 16 how do you know whether to use overcurrent or ungrounded conductor ampacity?

[@schulerruler]

It really depends what the conductor is. If it is just a regular ol' bond, then it is sized of the overcurrent as in 10-614 3). If there has been an increase in awg size for voltage drop them we use the ampacity of the largest ungrounded, also 10-614 3)

[@brimmedHat]

@@schulerruler ok thanks. If a test question only gives conductor size should I get the overcurrent setting/rating based on the conductors and use that?

[@schulerruler]

I would say yes, but remember if you know the load you are permitted to size up from the allowable ampacity of the conductor when using table 13, based off 14-104 1). If you don't know what the load is however you must go down at table 14. Again in accordance with 14-104 1).

[@michealgoudarzi6893]

Great teacher. Thank you.

[@DoctorFurter]

Great video. I was wondering if you or anyone would know when, or if, we would use the 60 degree column for ampacity? I've had some confusing questions from the practice IP where they use 60 degrees and I can't figure out exactly why.

[@schulerruler]

If your equipment temperature, or insulation temperature is 60, you would use the 60 column as per 4-006.

[@DoctorFurter]

@@schulerruler Thanks for replying. In the examples you're showing here, are we assuming that the termination temperature was marked as 75 degrees? 4-006 2) says we need to use 60 degrees when equipment temperature is not marked and is less than 100A.

[@muthukumarkanakasabai8454]

Nice explanation sir thank you very much

[@susanrustaie2225]

thanks alot for your vidoe. it helps alot.

[@schulerruler]

I'm happy to hear that! Thanks for the support!

[@m2agapay369]

You mean sir FLC or full load current? Coz as far as i know FLA will only use to sizing an overload

[@schulerruler]

Full Load Current or Full Load Amperage. Both equate to the same thing. Thanks for watching and commenting.

[@silliondelfish2176]

Hi,I'm doing a cecil question...a 3 phase synchronous motor,575 V, 30hp , sf 1.2, termination rating is 75c, p.f 0.9..the question requires minimum rw90 conductor, maximum standard circuit breaker and maximum overload device. I am having trouble on which table to use

[@schulerruler]

Table 44 synchronous motors footnotes tell you to multiply your corresponding FLA by 1.1 for a 90% power factor. This would be your FLA used for all calculations. To determine the overcurrent you would then use table 29 as usual to size. As far as conductors, I would assume it is continuous duty rated for calculation purposes.

[@viktorhrycek124]

Hi, can you please make video about short circuit calculations?

[@toumistra]

Could you use a smaller breaker on the first example, or do you have to use the highest breaker size. For example, could you use a 80 amp breaker? Much cheaper than the 125amp. Or is it because of the inrush current.

[@schulerruler]

Good question. Remember table 29 is our maximum setting of overcurrent device. Academically we go for the biggest possible overcurrent, to ensure consistency in selecting answers, but you could choose smaller than that in the field, but yes inrush could start to cause nuisance tripping if too small.

[@adnansaeed175]

First motor has S.F 1.1 which is less than 1.15, according to previous video, FLA should be multiplied by 1.15 instead of 1.25. what is the reason?

[@schulerruler]

In this video we are sizing the branch circuit conductors, and we use the 125% required to determine the minimum ampacity for a continuous motor. Check 28-106 1).

[@schulerruler]

If we were sizing overloads for this motor though we would use 1.15 to determine the maximum trip setting.

[@sdssds3933]

Excellent thank you

[@efrainhernandez983]

What's the minimum size for the circuit breaker?

[@MissionFitnessCTC]

Great video. Cheers!

[@schulerruler]

Thanks for watching!

[@Frnciss287]

Hi! May I just ask why did you use a smaller rating of breaker and fuse on both the circuit breaker? Have you not considered the inrush current of the starting of the motor? Is it not that the AT of the breaker and the rating of the fuse should be higher than what your calculated inrush current of the motor?

[@schulerruler]

The calculations done will allow inrush without tripping. These are the absolute maximum size overcurrent, and any larger would not be allowable. The percentages based off of table 29 in the Canadian electrical code are where this information is found. Thanks for watching and commenting!

[@Frnciss287]

@@schulerruler the 2.5 multiplier of the breaker, is it not that it is for the maximum inrush current of the motor? Any breaker rating below that calculated current would trip the breaker instantaneously after just starting the motor?

[@SuperAMG11]

Overcurrent Calculation = Size Down. Overload Calculation = Size up Sizing wires = Size up. Correct?

[@ductriphan5973]

I wonder how can the breaker protect conductor when the ampacity of overcurrent protection was chosen be higher ampacity of wire? thanks

[@schulerruler]

The current draw will not exceed the allowable trip setting of the overload device that is separately sized. In this case the breaker is sized to protect against short circuit condition only.

[@ductriphan5973]

thanks for your explanation

[@schulerruler]

@@ductriphan5973 happy to help!

[@javierpuerta8074]

excellent class

[@Al-wu8is]

🙏🙏🙏

[@silliondelfish2176]

Can you help

[@silliondelfish2176]

Please