Interested to Buy Any Domain ? << Click Here >> for more details...
when the rheostat kept in minimum to maximum position in
motors what will happen?
- 7 Answers
- 18416 Views
- I also Faced
- E-Mail Answers
Answer Posted / bhavani
In dc motor v=Eb-IaRa is the voltage equation.at starting Eb=0 so V=IaRa and the armature resistance is very small nearly 0.01ohm.so Ia increases ,to avoid this problem we kept 3-point starter.in motors field resistance is kept in minimum in order to get high starting torque.if v increases speed also increase and flux in field rheostat and field current are decreases. at the instant of starting to control the speed not to go beyond its rated value.that's why we kept field resistance in minimum.If we kept in maximum,R increases,I decreases,N increases so the motor will exceed its rated speed,then motor will damaged.or to avoid this probiem,we can control the speed of motor ,when armature rheostat is in maximum,voltage applied is minimum,so N decreases.so we will get rated speed by controlling any one of this.either by incresing applied voltage to armature or by decreasing the current in field winding.THANK YOU
| Is This Answer Correct ? | 4 Yes | 0 No |
Post New Answer View All Answers
What is different type of Electrical curve and how it protects the equipment's while up-normal situation?
can a 150 kva 3 phase 440v/230V delta-wye step down transformer can be use as step up transfoermer with connected loads at 440v side?
Why temperature rise is conducted in bus bars and isolators?
how can we select the appropriate VCB ?
in 1-phase 230v,how in 3-phase 440v. in each phase in between 230v.
I am getting above 60 V as open delta voltage against single phase unit ICT at tertiary delta formed and ICT getting trippped on NDR. ICT tested and found in order. PTs provided on tertiary are tested and in order. what may be the reason?
What is Surge Capacitor? Why it is require in Generator Circuit Breaker,inspite of surge arrester?
one electromagnet is called
Explain about how is it working Earth fault'relay and wahts the resistance value of earth bed
i wasted one year for the job after completed my btech what can i say about 1year time in interview
I am getting above 60 V as open delta voltage against single phase unit ICT at tertiary delta formed and ICT getting trippped on NDR. ICT tested and found in order. PTs provided on tertiary are tested and in order. what may be the reason?
How to calculate fault level of 11 KV system
Is potential difference materials property ..? if yes tnen how.. explain brifly.
Mention the disadvantages of low power factor?
What is the difference between resistance grounding system and resistance earthing system?
