What does a growler test for?
A growler is an electricity device used for testing insulation of a motor for shorted coils. A growler consists of a coil of wire wrapped around an iron core and connected to a source of alternating current.
How do you test a rotor?
HIGH CURRENT ROTOR TEST – This test is performed by applying high current through the shaft of the rotor (rotor out of stator) and thermally scanning (infrared or thermoscan) the rotor O.D. searching for shorted laminations. These shorted laminations cause localized hot spots which cause uneven heating of the rotor.
Can the growler be used to test the stator yoke coil?
The presence of a high current usually means that there are shorted turns somewhere in the coil. Along with the standard application, the growler can be used (source: wiki): to test shorts between turns in taped coils before installation into an armature or a stator. as a low voltage isolation transformer.
How many winding are there in a growler?
The growler acts as a transformer as before but here we have two secondary windings – the primary and secondary windings of the magneto armature.
What is difference between coil and winding?
In electrical|lang=en terms the difference between coil and winding. is that coil is (electrical) a coil of electrically conductive wire through which electricity can flow while winding is (electrical) a length of wire wound around the core of an electrical transformer.
How do you check a rotor with a multimeter?
Select the Ohms scale & place one of each testing probe onto each slip ring & check the ohms reading which should be low (e.g. 2–4 ohms) & you can check between the slip rings & the rotor frame which should measure infinity ohms !
How is rotor bar frequency calculated?
Loose or open rotor bars in AC induction motors are indicated by a 2 X line frequency (2 FL) sidebands surrounding rotor bar pass frequency and/or its harmonics (rotor bar pass frequency = number of bars X rpm).
When testing the windings in the stator which measurement should be used?
To test complete stator windings, the high voltage test supply must be rated in the 5 to 20 kVA range to energize the winding capacitance to rated line-to-ground or line-to-line voltage.
Which motor has starting winding as well as running winding?
Single-phase induction motors are not self-starting without an auxiliary stator winding driven by an out of phase current of near 90°. Once started the auxiliary winding is optional. The auxiliary winding of a permanent split capacitor motor has a capacitor in series with it during starting and running.
What is overhang and active portion of coil?
It is the part of a coil which lies in the slots under a magnetic pole and EMF is induced in this part only. In Figure 1(a), coil sides AB and CD are called as active sides.
What is a growler test?
The growler test is the first test used to determine discontinuities of current through a rotor bar, caused by blown-out wires, loose laminations, or cracking. It is performed with the rotor completely separated from its stator and connected to an armature growler – a coil of wire wrapped around an iron core connected to a source of AC current.
What is a Growler on a lawn mower?
This growler acts as an open-ended transformer that induces AC power into the rotor’s armature for the purpose of checking for the presence of shorted turns. The operators holds a feeler (typically a hacksaw blade) on top of the rotor and rotates the rotor around, looking for any area where the feeler vibrates, or “growls”.
What is an armature Growler and how does it work?
It is performed with the rotor completely separated from its stator and connected to an armature growler – a coil of wire wrapped around an iron core connected to a source of AC current. This growler acts as an open-ended transformer that induces AC power into the rotor’s armature for the purpose of checking for the presence of shorted turns.
What percentage do you test at for rotors?
When weather conditions allow, we will test at greater than 70%. No thermal or time dependance observed during vibration measurements. Without our involvment, the rotor was sent to a service shop for inspection and testing. A visual and growler test was all that was performed. Motor shop stated that no rotor defects were found.