Help with Shugart SA801 8" floppy with 230v 50 cycle motor...

[Jules Richardson]

Tony Duell wrote:
>> Fred Cisin wrote:
>>> OR, . . .
>>> modify your disk controller to run at a differnt bit rate
>> The motor's just a simple AC-driven affair, is it not? Replacing with a 
>> similar motor of the correct frequency would be another option, assuming that 
> 
> A clever trick if you can do it!.
> 
> You can't get jeut any speed from such a motor.

Yeah, I was rather posting when half asleep :-(

I suspect there might be a reasonable degree of commonality in small motor 
designs, but I think you're right - there's no guarantee that all small motors 
of a given design voltage / frequency will run at the same speed... (at least, 
alternator frequency is dependent on RPM and pole count, so the RPM for a 
motor is presumably dependent upon frequency and pole count)

>> I'm going to run into the same issue as the OP sometime, as I have a pair of 
>> SA800's to bring over to the US at some stage - I believe the spindle motor 
>> portion's exactly the same between the 800 and 801.
> 
> I thought the 800 and 801 were essentially the same drive anyway. The 
> spindle motor should tbe the same in the 850 series (double sided) too.

Yep, I think my brain was mixing 801 and 850 up :-)

(without checking, I believe the 80x drives are single-sided, and the 85x are 
double-sided variants - and the xx1 drives have some extra smarts on-board). I 
suspect there's a high degree of commonality between them all, particularly in 
the spindle drive (the double-sided drives presumably have some extra guts 
related to the second head)

cheers

Jules