Register to reply

Magnetisation Curve (Synchronous Machines)

Share this thread:
buildingblocs
#1
Oct23-13, 08:10 AM
P: 11
Hi All,

Today I conducted a lab in which we plotted the open circuit voltage (V[oc]) and closed circuit current (I[sc]) versus the excitation current in the rotor (I[x]).

From the data (plots are attached to thread), it can be seen that saturation occurs in the V[oc] versus I[x] curve however the I[sc] versus I[x] curve remains linear.

Why is it that saturation occurs only with V[oc] and not with I[oc] in the stator?
Attached Thumbnails
Voc.png   Isc.png  
Phys.Org News Partner Engineering news on Phys.org
Hoverbike drone project for air transport takes off
Student develops filter for clean water around the world
Developing the next evolution in underwater communication
gerbi
#2
Oct24-13, 08:28 AM
PF Gold
gerbi's Avatar
P: 160
Open-circuit curve (stator voltage vs excitation current) test is performed (or calculated) at zero stator current and 0-1,2 of rated stator voltage. In this case saturation of magnetic circuit is clearly visible.

Short-circuit curve (stator current vs excitation current) test is performed at shorted stator terminals 0-1.0 of rated stator current. Stator voltage (internal stator voltage) is quite low during the test, so you wont observe effects of saturation.

So why saturation is dependent on voltage ? Remember that equation: E=4,44*f*ψ*z
where: E-voltage (stator), f-freuqency, ψ-magnetic flux, z-number of turns

Frequency is static, numer of turs also. Only voltage and flux chanches, so: E≈ψ
The higher voltage, the higher flux is required. Higher flux means higer saturation.


Register to reply

Related Discussions
Synchronous Machines - Open Circuit and Short Circuit Tests Engineering, Comp Sci, & Technology Homework 3
Magnetisation curve Biology, Chemistry & Other Homework 0
Does the length of an iron bar changes when it is magnetised? Classical Physics 4
Magnetisation Curve and Hystersis Loop Classical Physics 1