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Responding to Slippies's query.... 1) Is your multimeter set on "Diode Test" position? 2) The meter's voltage may be too low. That is, the available test voltage of the multimeter may not be able to turn the IGBT on! Regards, Phil Corso, PE {Boca Raton, FL, USA} [[email protected]]...

Axially, of course! Regards, Phil Corso, PE {Boca Raton, FL, USA} [[email protected]] ([email protected]) {[email protected]}

A technical correction in defense of Hardacker's query: In the UK, formulas involving an AC motor's poles usually refer to pole-pairs. Regards, Phil Corso, PE {Boca Raton, FL, USA} [[email protected]] ([email protected]) {[email protected]}

Responding to Anshuman Patra's query: 1) Do the motors have to change speed together? 2) Have you investigated using an AC reluctance motor with an integral mechanical speed changer? Regards, Phil Corso, PE {Boca Raton, FL, USA} [[email protected]] ([email protected])...

Responding to Neevarp's query... The short answer is yes. However, the effectiveness of a capacitor for braking under conditions you specify is questionable. Search List Archive for: "Motion: Braking 3ph Induction Motor" Regards, Phil Corso, PE {Boca Raton, FL, USA}...

Responding to Anonymous' query.... What are you trying to "Control?" Regards, Phil Corso, PE {Boca Raton, FL, USA} [[email protected]] ([email protected]) {[email protected]}

Martin, I apologize for sending you on a wild-goose chase. The Aug '99 post referencing the formula(s) is no longer available in the Archives. So, here it is again: Given a 3-phase system in which the total capacitive reactive power is kVARc, and line-to-line voltage is kV, then 3...

Responding to Troll's query... The following procedure will provide a good approximation: 1) There are 4 "ON" operations per cycle. Label them A, B, C, and D. 2) Determine the current for each operation. Label them Ia, Ib, Ic, and Id. 3) Determine the duration of each operation...

Responding to Martin's query: The formula(s) you seek can be found in the List Archive under "APPS: HT Capacitor Bank Failure"! Regards, Phil Corso, PE Boca Raton, FL [[email protected]] ([email protected]) {[email protected]}

Responding to Anonymous' query... You have two distinct and separate situations: A) Fusing of Directional Contactor. If there is a probability of such an event, then you must consider contactors having different materials to preclude, or at least ameliorate the conditions causing...

Kumar, The connection you detail is (typically?) used to reduce the duty on the mechanical brake during lowering of the load. Apparently, someone felt that the mechanical brake wear was unusual. Have you posted the original query because you feel that motor performance, or life...

If the oriiginal apparent load, kVAo, the original power factor, PFo, and the required power factor, PFr, are known, then the formula for capacitive reactive power, neglecting capacitor loss, is: kVAc = K x P, where K = tan [ Acos ( PFo ) ] - tan [ Acos ( PFr ) ], and, P = kVAo x...

Responding to Gray's query: Here is what worked for me in some cases. If Probabilistic Risk Analysis, PRA, shows that there is a consequential increase in thrust pad temperature, then, it can replace the redundant displacement probe! Regards, Phil Corso, PE Boca Raton, FL...

Responding to Jim Roswell's Sat, Dec 27, 2003, 6:53pm, denunciation of my comments on the subject: Jim, I believe that you are comparing "apples" to "oranges'. That is, you are considering only operation at extreme supply voltages! Paragraphs A and B in my original reply addressed supply...

Pkumar, Your explanation needs to be further detailed. The delta-connected rotor winding remains connected in delta. 1) By rotor single-phase, are you referring to one element of one-phase of the resistance bank? Is it open-circuited for both directions? 2) How is the 'star'...

Responding to Joe Jansen's query. Here is a start or direction, if you will: 1) Convert area to kcmil. 2) Use analytical geometry to determine remaining area after deducting cut-away area. 3) Use I.M. Onderdonk's formula in Fink & Carroll's "Standard Handbook for Electrical...

<p>For Anonymous: <p>The following formula will yield the minimum wire size to satisfy a voltage-drop requirement. However, it will not provide the size based on construction, installation, and operating conditions: <pre> S = Kp x Kc x L x A / Ed, where, S = cable area (units shown...

Following is an approximate method for determining pf. Determine the motor's temperature, Tm. Calculate the temperature-rise above ambient, Tm - Ta. Ratio this to the rated temp-rise, Tr, found on the nameplate. Determine pf as follows: kWo = [(Tm - Ta) / Tr] x rated kWr], where...

Paraphrasing the not too famous Kennedy, George, "Gentlemen, what we have is a case of simple mis-communication": Fred: The "potential" energy stored by the capacitor is 1/2xCxV^2, in Joules. When the capacitor is series connected to a resistor, R, then the potential energy is converted to...

Responding to H. Shazad's query: The Amp-hour "capacity" is determined by integrating the current-time curve of the current transient... in other words, the area between the current curve and the horizontal or 't' axis. Note that such a curve is related to the discharge resistor, R...