What exactly is a "Synchro-Lab" motor?

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Belmont
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What exactly is a "Synchro-Lab" motor?

Post by Belmont » 01 Oct 2019 19:53

I've owned a SL95 for a while, and used to have an SL65B, and I'm just wondering what kind of motor the Synchro-Lab motor is. I take it that it's a synchronous motor, but others have referred to it as a hybrid?

aardvarkash10
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Re: What exactly is a "Synchro-Lab" motor?

Post by aardvarkash10 » 03 Oct 2019 06:47

the received design wisdom is that it is a combined synchronous and induction motor - the induction section gives rapid start up, the synchronous section the speed stability tied to line frequency.

My background is all in DC stuff - AC confuses me, so I don't claim to have any ability to assess that belief. However, Garrard made statements to that effect in their advertising copy so it must be at least half true.

Coffee Phil
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Re: What exactly is a "Synchro-Lab" motor?

Post by Coffee Phil » 03 Oct 2019 07:47

Hi aardvarkask 10,

Your AC motor chops must be pretty good. That is the correct answer. One other virtue of a hystereses synchronous motor is that since the rotor is a hard steel ring, if it is symmetrical about the axis balance is a given. Not as much with an induction motor with its squirrel cage rotor. I believe the better approach is to use a sufficiently large hystereses synchronous motor such as the lovely outer rotor motor in my R-O-K Rondine 2.

I believe Pioneer used a similar motor in some of their machines such as the PL12 but since Gerrard likely trade marked the cutesy name Pioneer just called theirs a synchronous motor without a mention of the starting “help” it received from the squirrel cage section of its rotor.

Phil

aardvarkash10 wrote:
03 Oct 2019 06:47
the received design wisdom is that it is a combined synchronous and induction motor - the induction section gives rapid start up, the synchronous section the speed stability tied to line frequency.

My background is all in DC stuff - AC confuses me, so I don't claim to have any ability to assess that belief. However, Garrard made statements to that effect in their advertising copy so it must be at least half true.

A70BBen
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Re: What exactly is a "Synchro-Lab" motor?

Post by A70BBen » 04 Oct 2019 00:14

Garrard actually held the patent on the induction/synchronous design. Pioneer, Dual, Elac and most of the rest were licensed by Garrard to use the design. Garrard made healthy revenues from licensing of their patents; that was not the only significant one.

Horsetrading occurred, too. Matsushita built the induction/synchronous motors for Garrard's GT models that didn't have DC servo motors, and reportedly paid no license fees for motors that went into their own products; they also made the motors and provided the drive circuitry designs in the Garrard GT35 and GT55 series; and Matsushita also supplied the direct drive motor on the Garrard DD75.

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Re: What exactly is a "Synchro-Lab" motor?

Post by Coffee Phil » 04 Oct 2019 02:03

Hi A70BBen,

I had no idea they had a patent on that. I’m amazed that putting a squirrel cage rotor and hystereses rotor on the same shaft would be patentable. Well I suppose it is innovative and allows a synchronous motor in a smaller less expensive size. I wonder what the trade-off would be with a reluctance synchronous motor.

Phil



A70BBen wrote:
04 Oct 2019 00:14
Garrard actually held the patent on the induction/synchronous design. Pioneer, Dual, Elac and most of the rest were licensed by Garrard to use the design. Garrard made healthy revenues from licensing of their patents; that was not the only significant one.

Horsetrading occurred, too. Matsushita built the induction/synchronous motors for Garrard's GT models that didn't have DC servo motors, and reportedly paid no license fees for motors that went into their own products; they also made the motors and provided the drive circuitry designs in the Garrard GT35 and GT55 series; and Matsushita also supplied the direct drive motor on the Garrard DD75.

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