Linear Motor Quartz-Locked PLL Direct-Drive Turntable
The Fisher MT-6250 direct drive turntable employs a very unique linear motor drive system, very different from some of the other direct-drive turntables on today's market.
If a comparison is made, the most obvious difference is the utmost simplicity of the Fisher MT-6250; and since this is an electromechanical device, simplicity translates into long-term stability and reliability.
Some of the most outstanding features of this unique drive system are that the turntable platter is the rotor of the motor, that there are no electrical connections to the rotor, that the rotor has no armature windings and that all the complicated electronic circuitry is in a stationary (non moving) position on a single PC Board mounted into the turntable base.
The linear motor used in the MT-6250 moves and accelerates upon the application of a 3-phase drive signal at a frequency of either 33 1/3 Hz or 45 Hz to 3 stator field coils. The 3-phase drive signal produces a progressively changing magnetic field in the stator windings. This magnetic field will attract and repel (or pull and push) the respective magnetic poles of the rotor magnets and thus cause the platter to rotate.
Inertia causes the rotor to turn past the exact position of North Pole and South Pole alignment, and at this instant the magnetic field advances or rotates, thus pulling and pushing the rotor again in the same direction.
Type: fully automatic turntable
Motor: 120 pole linear quartz, phase locked loop
Drive system: direct drive
Wow and flutter: 0.03%
Speed control range: +-6% (quartz lock off)
Platter: 12-15/16 inches, 2.2lbs
Speeds: 33 and 45rpm
Effective length: 222mm
Dimensions: 17-3/4 x 14-1/4 x 6-1/2 inches
Weight: 18.7 lbs
Base finish: walnut grain vinyl
service manual - odduramone
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Fisher MT-6250 / MT6250 owners manual, service manuals and schematics are for reference only and the Vinyl Engine bears no responsibility for errors or other inaccuracies. The PDF files are provided under strict licence. Reproduction without prior permission or for financial gain is strictly prohibited. This website is not affiliated with or sponsored by Fisher.