PROTOTYPE BRUSHLESS MOTOR OBJECTIVES

  Top quality brushless motor
Speed feedback sensors built into controller
Top quality brushless controller
Best available power supply (even better if it can run from battery)
High quality motor bearing
RPM approx 300 rpm would be ideal (for similar size pulley as we use at the moment)
Small size and high momentum and quick start up time
Extra low vibration needed

Ideally we need a feedback check on the motor to maintain constant speed, a high quality brass bush bearing …or ball raced…should give little or no noise…

Especially if the motor RPM is low …even less vibrations/hum

 High filtered mains power supply is expensive and in some cases unreliable …new lithium polymer or NIMh batteries will give stable power. So the operating voltage of the motor needs be very low…. and the big plus is that the power supply only needs be a simple charger …like a Nokia phone charger for example (just under 4volts for the NIMh batteries)

 Plus in theory the more batteries you have the better

 Ideally we need the motor to fit inside existing space in all turntables…so little conversion is need to fit on any turntable

FLOPPY CONVERSION -----has all the above-----

 BASIC FLOPPY DRIVE is very cheap…

But the electronics controlling it are very sophisticated and the bearing is very good quality… and can be replaced if necessary

Remove the top cover:

 Normally just a few screws …or in this case just a screwdriver to lift up the back ends

remove the screws on underside to take bottom cover off

 Unit now needs the heads and metal floppy cage removed

 @ The bottom 6 screws hold the PCB onto the metal frame

…Remove the 6 screws

 Now we have the basic PCB visible

This is now getting to a stage we can almost test it…

The plastic strips on top of motor, I removed them with a sharp knife

(How to connect the correct pins and cheat the sensors will come later)

Spindle simply pulls off J - this makes cleaning very easy

Motor magnet and main spindle removed for inspection

 Clock timer and processor controller now flipped under the motor board and test pulley fitted on top of spindle

We will be trimming the PCB smaller later

 neat!!! -WORKING PROTOTYPE –

 The 33-rpm and 45rpm 2-step pulley made from ally (will be turned down to ½ the size seen here look below)

Also the PCB area will be trimmed down to much smaller

And to save time I have glued the pulley on with super glue….

…The tidy up will come much later!

 I have already got the sizes I need for the 33 rpm…the 45-rpm I have just guess for the moment J

3.6volt NIMh battery powers this unit for days and days…current draw with the led fitted is 20ma ß- my meter must be faulty …surly J

 CONCEPT----- Nokia charger (or similar) can recharge the batteries…

Also the unit can be used worldwide. …Used with your own phone charger J

I'll need a simple charge- cut off- circuit…. the parts are cheap

 BEARING removed …simple but high quality bush bearing with black nylon thrust plate…. we are going to isolate the main bearing from the PCB/…but still keep it earthed to the copper on the PCB (stops static)

 Small amount of silicon rubber solution @ the bottom of bearing will isolate it much better  @ this stage …plus the silicon will help make a seal to hold oil in our brass bush bearing

 PULLEY tidied up- this 1 made from easy-machined aluminium 33 and 45rpm

 FITTING TO THE TEST BED