Motor Electrical And Mechanical Formulas

101.5K views

Up next

45kV, 66kV, 110kV, 132kV, 220kV And 330-420kV Transmission Line Steel Towers

45kV, 66kV, 110kV, 132kV, 220kV And 330-420kV Transmission Line Steel Towers

69K Shares
0
0
324
0
0
0
0
0

Engineering Formulas

Quantity	Symbol	Unit	Symbol	Example
apparent power	S	Voltage x Current	VA	120kVA (1000 x V x I )
current	I	Ampere	A
efficiency	η	per unit		0.95 (i.e. 95%)
frequency	f	Hertz	Hz	50 Hz
poles	p	number		2 pole, 4 pole
pole pairs	pp	number		4 pole is 2 pp
active power	P	Watt	W	kW = 1000 x W
power, input	P_in	Watt	W
power, output	P_out	Watt	W
power factor	pf	per unit		0.86
reactive power	Q	Voltage x Current reactive	var
slip	s	per unit
speed	N	revs per minute		Not SI unit
torque	T	Newton . metre	Nm
voltage	V	Volt	V

Quantity	DC	AC 1 Phase	AC 3 Phase
Current (I)	$\frac{P_{out}}{V\times\;Efficiency}$	$\frac{P_{out}}{V\times\;Efficiency\times\;Power\;Factor}$	$\frac{P_{out}}{\sqrt{3}\times\;V\times\;Efficiency\times\;Power\;Factor}$
Efficiency	$\frac{P_{out}}{V\times\;I}$	$\frac{P_{out}}{V\times\;I\times\;Power\;Factor}$	$\frac{P_{out}}{\sqrt{3}\times\;V\times\;I\times\;Power\;Factor}$
Power Factor		$\frac{P_{in}}{V\times\;I}$	$\frac{P_{in}}{\sqrt{3}\times\;V\times\;I}$

Formula

Quantity	Formula
Fan load power	$Hp=\frac{ft^{3}/min\times\;pressure\;(lbs/ft^{2})}{33,000\times\;Fan\;Efficiency\;(p.u.)}$
Fan load power	$kW=\frac{Flow\;(m^{3}.s^{-1})\times\;pressure\;(kPa)}{Fan\;Efficiency\;(p.u.)}$
Ohm’s Law (Resistive circuits)	$V=I\times R$	$I=\frac{V}{R}$	$R=\frac{V}{I}$
Power (kW)	$kW=\frac{T(N.m)\times rpm}{9550}$
Power (Hp)	$Hp=\frac{T(lb.ft)\times rpm}{5250}$
Power Factor	$Power\;Factor=\frac{P_{in}}{V\times I}$
Pump load power (Hp)	$Hp=\frac{Galls/min\times Head(ft)\times Specific\;Gravity}{3960\times Pump\;Efficiency(p.u.)}$
Pump load power (kW)	$kW=\frac{9.81\times Head(m)\times Specific\;Gravity}{1000\times Pump\;Efficiency(p.u.)}$
Slip, s, (p.u.)	$s=\frac{N_{s}-N}{N_{s}}\times 100$
Slip, (%)	$s(_{o}/^{o})=\frac{(N_{s}-N)\times 100}{N_{s}}$
Synchronous speed, N_S, (rpm)	$N_{s}=\frac{Hz\times 120}{p(poles)}$
Torque (N.m)	$T=\frac{kW\times 9250}{rpm}$
Torque (lb.ft)	$T=\frac{Hp\times 5250}{rpm}$

Watch this video for more information

Share this

0 0 votes

Article Rating

Subscribe

0 Comments

Newest

Oldest Most Voted

Inline Feedbacks

View all comments

Javascript Disabled!

Please Enable Javascript if you disabled it, or use another browser we preferred Google Chrome.

Please Refresh Page After Enable

Powered By UnCopy.