Home Page News Search Contact Us Language Bar فارسی English
If you have faced with a case that needs conferring during your work or studies, you can submit it here as a "New Riddle" and we'll show it in your name. Notice: Site owners have the right to accept a riddle or not, or make a little changes in submited riddles.
Submit New Riddle

Recently I participated in a generator electrical test program. Measuring of Stator winding  resistance is also of the mentioned tests.
Author : Hamid - From: Iran

One electromotor serviceman who worked in a small workshop needed an ac power supply with 100HZ frequency.
Author : Hamid

Mayor of a mathematical city promised that electrical energy will be free for their future citizen, because they will consume no energy for electrical power generation!!
Author : Hamid
In static excitation system (with brush)of large power plant generators
excitation voltage is supplied by 3-ph excitation transformer with typical vector group YD5 or DY5.
Author : VATKARI from INDIA
An industrial power system includes one gas turbine generator (6KV, 12 MW), a step up transformer (6/20 KV, Dyn11, 20 MVA) and relevant distribution system.
Author : Hamid - From: IRAN
What is the purpose of Partial discharge measurement in generator? Pls.Explain with theroritical measurement principle.
Author : Ganesh - From: INDIA
i am working in a motion capture project one of its parts is a sensor
i need a formula of the voltage generated in the coil due to moving in electromagnetic Field from an inducer
Author : GUEST
is there any relation between speed of motor and power factor?
Author : GUEST
How do i design for a capacity of a Generator to be use in factory and bank?

Author : GUEST
Please explain about reacceleration scheme of motors.
Author : GUEST
Can I use 50HZ motor in 60HZ system and vice versa?
Author : GUEST
Whether can we start a synchronizing motor similar an induction motor?
What points shall be considered?
Author : GUEST
hi, i have a question that whether it is possible for an 3phase induction motor operating as synchronous motor.
Author : suchismita ghosh - From: INDIA

When a generator is operating in parallel with another same size generator, what will be the effect of changing governor set points and field currents?
Author : SAEID - From: IRAN
In power generation plant with several ungrounded generators and grounding only one generator, how can unearthed generator affecte from network earth faults?
Author : SAEID - From: Iran
Energy savings with lower frequency
We are consuming 50,000 Wh per day with 50 Hz 435 V , But when we reduce the frequency to 49 Hz , conumption will reduce to 2000 Wh
Author : A.Selvakumar - From: India
effect of increased voltage on motor
Author : A.Selvakumar - From: INDIA
We have a generator feeding into an incomer, along a distance of about 15m. during ac pressure tests it was fine, all the phases and neutral were tied down to earth, and each one was tested individually.
Author : atiq - From: England
I need three phase voltage, how can I obtain it? In my house we just access to one single phase counter as main power supply.
Author : NADER
What will happen if we carry the generator tests at half of the rated condition?
Author : Wraith - From: Bangladesh
It is well known that, if an Alternator is connected with Grid its (alternator) voltage can not be change and it follows the grid voltage but i've seen that when its excitation changes its voltage also changes, why?
Author : Yogi - From: India
What is run of new motor drive with VVVF drive? Is it compulsory for every new motor?
Author : YOGI - From: India
What are Park's equations and its benefits?
Author : Naser - From: Qatar
How much KW capacity of motor is required to produce 5560 m3/hr air, how it has to be calculated?
Author : A.Selvakumar - From: India
Is it possible to power supply of small power electromotor via usual electronic UPS?
Author : Farzin - From: Iran-shiraz
how to run an induction motor as synchronous motor?
Author : Pratik
What would happen if I reverse the field current(excitation) of a three phase alternator?
Author : Sivakumar - From: Tamil Nadu-Chennai
Generally the field of the alternator is made the rotor.
Why is this done in this way?
Why shouldn't it be the other way?
Author : Sivakumar - From: Tamil Nadu-Chennai
What are the transient and sub transient concepts? Which phenomena cause transient and sub transient behavior of a generator in short circuit conditions?
Author : Ahmmed - From: Qatar
In an alternator, why does the induced EMF lags the main field flux by 90°?
Author : Sivakumar - From: Chennai
Why airgap flux can't change instantaneously in synchronous machine when short circuited?
Author : Abhishek Kumar - From: India
Is the rule of thumb that the size of capacitor required for PFC of an induction motor is sq rt of 3 x line volts x no load current x 0.8 correct?...
Author : Sinnadurai Sripadmanaban - From: Srilanka
Significance of shaft voltage/current in induction motors ...
Author : Sinnadurai Sripadmanaban - From: Srilanka
In two-elevator buildings where lift wells are located side by side instead of two separate motors if we connect the two lift cars by a single rope and connect to a single motor and control by a single PLC can we save energy?...
Author : Sinnadurai Sripadmanaban - From: Srilanka
What are the differences between NEMA and IEC/BS designs of induction motors?
What are the advantages/disadvantages of the two designs?...
Author : Sinnadurai Sripadmanaban - From: Srilanka
What are the differences among variable speed,variable frequency and inverter drives? Can normal motors be used for above use?
Author : S.Sripadmanaban - From: Srilanka
Which voltage is better for a 1000kW motor? 3.3kV or 6.6kV or 11kV? What is the criteria of selection of voltage based on its kW rating for a motor? Please explain
Author : V.K.Nambiathiri - From: India
I need to know a few thing about the speed torque curves of DC motors. Firstly, what's the formula of Stall torque and that of no-load speed of motor...?? ...
Author : Jawad Ahmed - From: Pakistan
How to connect common mode voltage source of induction motor with bearing equivalent model for simulation studies and motor equivalent parameters.
Author : Sharan reddy - From: India
The no load current of the induction motor should be less than 30% of rated load current. Is this a standard?...
Author : Manish Gautam - From: India
What is synchronizing coefficient of synchronous machine? Its equation and conditions for stable and unstable system.
Author : Manish Gautam - From: India
While the positive sequence reactance  has different values during sub transient, transient and steady state periods, why these are not applicable for negative sequence reactance. Why there  is no sub transient or transient negative sequence reactance?
Author : D.Suryanarayana - From: India
I am having LAVT panel iwth 6.6KV/415V transformer connection in the panel i want to supply 200N to the AVR panel. I am having Yy11 vector group in LAVT panel and want know whether i should give ...
Author : Javed alam khan - From: India
If we start a synchronous motor with field winding short circuited (no exitation) then we are sure that it will start as induction motor but, will this motor run as synchronous motor ??? or it will run as induction motor. pls explain in detail.
Author : RAMJEE KUMAR - From: India
How much speed can be increased of a dc motor with the help of field control method?
Author : Unknown
what is the difference between distribution breaker & generator circuit breaker
Author : deepak tardalkar - From: India
100 HP motor is driven through variable frequency drives, capacitor is connected in secondary side of VFD. What are the problems that may arise?
Author : soman - From: India
What is the differance between electrical and machanical power? If you have a 550Kw gearbox do you need a 550Kw electric motor to turn it???
Author : Unknown
Why the variations of the air gap flux determine the transient characteristic of the short-circuit current? ...
Author : adrian szetu - From: Australia
what will happen if negative terminal of a device is connected to the earthen  pot?
Author : Harshika - From: India
How should we proceed to size a  large storage battery bank  for solar power whose load contains different sizes of lamps,ac,motors etc
Author : sinnadurai sripadmanaban - From: srilanka
What is subtransient & transient reactances. how it is different than steady state reactances . and why low values will be prefered usually?
Author : Unknown - From: India
if suppose frequency is reduced in a transformer keeping the voltage as same the value of flux will decrease.What will its effect on performance of transformer as in comment about the new kva rating,variable and constant losses,magnetising current etc...!!
Author : Ketan - From: India
Why we use  three phase transmission in present ,instead of 4 phase or above,why we are not use 4 phase and above....
Author : Naman
Plzz explain technically concept means actual meaning in reality of active power,reactive power,and apparent power..
Author : Naman
Plzzz explain the concept that....In d.c motor the resistance of outer cage is more as compare to inner cage,and the reactance of inner cage is more as compared to outer cage...
Author : Naman
Why in AC sinsudial wave is come in function generator also,and why we use or draw sinsudial wave instead of square wave or ...
Author : Naman
In a plant electric motors have not been tested regularly for some years, what tests shall be done to evaluate their conditions?
Author : Mohsen Noori - From: Iran
Why the synchronous generators connected in parallel in the network system have different power factor?
Author : Supratim - From: India
Dear Sir,
First of all, please accept my  thanks for your great and valuable assistance.
To set function ANSI 49 for protection of electromotors, motor thermal time constant is needed which should be specified by motor manufacturer. ...
Author : Mohsen Noori - From: Iran
Change Language :