I have an old Deagan vibraphone I'm restoring. It's an instrument made in Chicago and imported to the UK in the 70s.
I want to be able to use it in the UK (240V line voltage) without having to use a 240v > 110v transformer, which is annoying to have to lug around to gigs and also adds ti to the weight of everything I'm carrying.
The motor is this Model 0737 - K-2 Series Parallel Shaft AC Gearmotor - AC Parallel Shaft Gearmotors - Bodine Electric
In the control panel is a 1uF capacitor rated at 250vac, a VR and this adjustable voltage regulator CSR1004A | United Automation, 230 V Voltage Regulator, 10A, Adjustable 3-Pin CSR1004A | RS Components which is rated at 230vac. It's wired up as in the schematic on the controller datasheet.
Will I be able to run it directly at UK mains voltage and get it in the right speed range just by adding a resistor in series with the VR on the controller? Or am I misunderstanding how it works?
Thanks!
I want to be able to use it in the UK (240V line voltage) without having to use a 240v > 110v transformer, which is annoying to have to lug around to gigs and also adds ti to the weight of everything I'm carrying.
The motor is this Model 0737 - K-2 Series Parallel Shaft AC Gearmotor - AC Parallel Shaft Gearmotors - Bodine Electric
In the control panel is a 1uF capacitor rated at 250vac, a VR and this adjustable voltage regulator CSR1004A | United Automation, 230 V Voltage Regulator, 10A, Adjustable 3-Pin CSR1004A | RS Components which is rated at 230vac. It's wired up as in the schematic on the controller datasheet.
Will I be able to run it directly at UK mains voltage and get it in the right speed range just by adding a resistor in series with the VR on the controller? Or am I misunderstanding how it works?
Thanks!
A challenging question.
What I believe the speed regulator does is conduct on just part of the AC cycle, depending on where you put the control "level". So you may get away with double the rated voltage of the motor - as long as you dont turn it up too far, i.e. to where it's conducting the majority of the UK mains level into the US mains motor. So your idea of modifying the control range with an additional resistor may work.
As its not a simple sine wave coming out of this controller, maybe you need to use a true RMS meter or oscilloscope to select the right range limiting resistor value and verify operation. I assume the "vibra" frequency is set to taste. Is it something that needs to change often, or is it a "set and forget - this is my sound" situation? FAIK, you set the vibra frequency to the meter of the song being played.
One engineer told me he could reduce the speed of a fan motor simply by putting a capacitor in line with the AC. He said it worked by shifting the phase of the current, relative to the voltage - and that it did this with no power dissipation. If your vibra frequency is fixed, maybe with just the right capacitor, you could run the 110 motor on 240 without burning it...
They didnt say what type of motor it was (induction?) in the .pdf I looked at. They did mention that the capacitor shown could experience higher voltage than the AC mains, hence I assume the 250V unit for the 110V input. I assume this could stay the same for the range-limited control modification. Good luck with it!
What I believe the speed regulator does is conduct on just part of the AC cycle, depending on where you put the control "level". So you may get away with double the rated voltage of the motor - as long as you dont turn it up too far, i.e. to where it's conducting the majority of the UK mains level into the US mains motor. So your idea of modifying the control range with an additional resistor may work.
As its not a simple sine wave coming out of this controller, maybe you need to use a true RMS meter or oscilloscope to select the right range limiting resistor value and verify operation. I assume the "vibra" frequency is set to taste. Is it something that needs to change often, or is it a "set and forget - this is my sound" situation? FAIK, you set the vibra frequency to the meter of the song being played.
One engineer told me he could reduce the speed of a fan motor simply by putting a capacitor in line with the AC. He said it worked by shifting the phase of the current, relative to the voltage - and that it did this with no power dissipation. If your vibra frequency is fixed, maybe with just the right capacitor, you could run the 110 motor on 240 without burning it...
They didnt say what type of motor it was (induction?) in the .pdf I looked at. They did mention that the capacitor shown could experience higher voltage than the AC mains, hence I assume the 250V unit for the 110V input. I assume this could stay the same for the range-limited control modification. Good luck with it!
It is actually easier to +increase+ RPM of a small induction motor with a series capacitor. IIRC 2uF series to a 69W induction fan raised fan speed about 20%. When I threw it at SPICE, indeed the resonance can increase motor voltage.
The vibraphone motor is very low power. A small autotransformer can be fitted and is "more correct" than using half the pot.
Ah I didn't realise that that was how it worked! I assumed it was acting like a big variable resistor and dissipating the unused power as heat!
Unfortunately I do need to be able to adjust the speed through the full range while I'm performing. I use different speeds depending on the song, tempo and style. You don't set it to fit in tempo wise with the song any more than you might try and match the speed of a Leslie on a Hammond or tremolo on a guitar to an exact tempo; it's more like a sound effect than anything.
If it's just a matter of reducing the voltage into the motor... couldn't I just use a resistor in series between the controller and the motor? Like you get ballast tubes in old series filament radios and such...
Unfortunately I do need to be able to adjust the speed through the full range while I'm performing. I use different speeds depending on the song, tempo and style. You don't set it to fit in tempo wise with the song any more than you might try and match the speed of a Leslie on a Hammond or tremolo on a guitar to an exact tempo; it's more like a sound effect than anything.
If it's just a matter of reducing the voltage into the motor... couldn't I just use a resistor in series between the controller and the motor? Like you get ballast tubes in old series filament radios and such...