0
\$\begingroup\$

I saw this AC motor parameter calculator online: http://www.engineeringtoolbox.com/electrical-motor-calculator-d_832.html

It says for 100 Horse power, in 90% efficiency, 0.9 Power Factor and 220 V AC supply, 300A current is needed. But when I calculate like:

220V AC * 300 A AC * 0.707 (sine root mean sq) * 0.9 (PF) / 745.7 W (1 Horse power) = 56.3 HP

Where do I confuse about the calculation?

Also, for a special purpose, I need to calculate the horsepower based on current flow in windings. In these windings below:

ac stator

Because I only know my inductance(L) value, radius(R), turns(N) and RMS current which is going to flow through these winding coils. I know these below;

L = 60 mH

R = 5 cm

d(wire diameter) = 0.4 mm

N = 210

And RMS current for each phase (current flow on armature windings) is 12 A (peak to peak)

how can I calculate the horse power by only these parameters? Can I be sure that this parameters are whether enough or not enough to drive a car? Thanks.

\$\endgroup\$
  • 2
    \$\begingroup\$ 220V already is the RMS value. \$\endgroup\$ – JimmyB Oct 18 '16 at 14:42
  • \$\begingroup\$ @JimmyB Oh sorry. I editted the calculation, now its 56 HP. Still not satisfying. \$\endgroup\$ – Alper91 Oct 18 '16 at 14:46
  • 1
    \$\begingroup\$ Your link is broken. \$\endgroup\$ – JimmyB Oct 18 '16 at 14:48
  • \$\begingroup\$ And do away with that 1/sqrt(2) factor. \$\endgroup\$ – JimmyB Oct 18 '16 at 14:48
  • 1
    \$\begingroup\$ Oh, you're talking about 3 phase. In that case the voltages to use are different. A factor of sqrt(3) may be required. \$\endgroup\$ – JimmyB Oct 18 '16 at 14:55
3
\$\begingroup\$

Three phase motor:

$$P=\sqrt{3}\cdot U \cdot I\cdot cos\varphi $$

$$P =1.73\cdot 220\cdot300\cdot0.9 \approx 100kW$$

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.