Output from Lucas Special Equipment Dynamo too high ?

[Clive Sherriff]

Is the output from my Lucas Special Equipment Dynamo too high ?

Having lost charge, I'm testing the output from a Lucas Special Equipment Dynamo and don't have any specifications for this uprated unit.

I am testing by connecting the F and D terminals together, then putting a voltmeter between the earth of the dynamo casing, and the linked F and D terminals.

Then, driving the dynamo with a drill at about 2500 rpm it's turning out 27 Volts which seems somewhat high for the voltage regulator to have to deal with

Any opinions ? ? ?

Clive

Oxford UK

m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

[img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1524777755&sig=TsLu9kfaO6DGDr6EyVuZPg--~D[/img] Virus-free. www.avast.com

[eworpe]

Hi Clive, 27 volts from a dynamo with its Field directly connected to the Dynamo output may not be unusual. The voltage regulator modulates the dynamo output voltage by varying how much of the dynamo output is fed back into the field coil. This is achieved by the field relay contacts making and breaking many times a second, analogous to pulse width modulation. Initially the contacts are closed so that the dynamo output feeds directly into the field coil. This produces a quick build up of the dynamo output when starting the engine. Within a fraction of a second the initial high voltage & current pulse flowing through the field solenoid in the regulator forces the relay contacts to be opened leaving a 67 ohm resistor in circuit. The reduced dynamo output allows the field relay contacts to close, setting up another high charge pulse, the average current of these pulses is revealed by the ammeter. Perhaps a better test would be to load the dynamo output ( F & D connected ) with say a headlamp bulb and slowly increase engine revs to see if the dynamo can drive a load. It's often the case that after a long rest period, the field contacts need to be cleaned. Hope this helps, Eric. ________________________________________ From: CLIVE SHERRIFF csherriff99@gmail.com Is the output from my Lucas Special Equipment Dynamo too high ? Having lost charge, I'm testing the output from a Lucas Special Equipment Dynamo and don't have any specifications for this uprated unit. I am testing by connecting the F and D terminals together, then putting a voltmeter between the earth of the dynamo casing, and the linked F and D terminals. Then, driving the dynamo with a drill at about 2500 rpm it's turning out 27 Volts which seems somewhat high for the voltage regulator to have to deal with

[jeffrey townsend]

Hi Clive,

I am no electrician but thought it worth asking if this is a 3rd brush SE unit as fitted to the TB? If so won't the output vary depending on the brush position?

Regards,

Jeff    TA1957  TB0489      Cambs UK 

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of CLIVE SHERRIFF csherriff99@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] 24 April 2018 19:25 [b]To:[/b] yahoogroups [b]Subject:[/b] [mg-tabc] Output from Lucas Special Equipment Dynamo too high ?     Is the output from my Lucas Special Equipment Dynamo too high ?

Having lost charge, I'm testing the output from a Lucas Special Equipment Dynamo and don't have any specifications for this uprated unit.

I am testing by connecting the F and D terminals together, then putting a voltmeter between the earth of the dynamo casing, and the linked F and D terminals.

Then, driving the dynamo with a drill at about 2500 rpm it's turning out 27 Volts which seems somewhat high for the voltage regulator to have to deal with

Any opinions ? ? ?

Clive

Oxford UK

m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm

[img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1524777756&sig=r10oMnwxuIl1c4X3nUdMBA--~D[/img] Virus-free. www.avast.com

[Clive Sherriff]

Hi Jeff,>> worth asking if this is a 3rd brush SE unit as fitted to the TB? No, its not a Three Brush but the Two Brush unit. Clive

On Thu, Apr 26, 2018 at 9:11 AM, jeffrey townsend jeff.townsend@hotmail.co.uk> wrote: Hi Clive,

I am no electrician but thought it worth asking if this is a 3rd brush SE unit as fitted to the TB? If so won't the output vary depending on the brush position?

Regards,

Jeff TA1957 TB0489 Cambs UK

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of CLIVE SHERRIFF csherriff99@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] 24 April 2018 19:25 [b]To:[/b] yahoogroups [b]Subject:[/b] [mg-tabc] Output from Lucas Special Equipment Dynamo too high ? Is the output from my Lucas Special Equipment Dynamo too high ?

Having lost charge, I'm testing the output from a Lucas Special Equipment Dynamo and don't have any specifications for this uprated unit.

I am testing by connecting the F and D terminals together, then putting a voltmeter between the earth of the dynamo casing, and the linked F and D terminals.

Then, driving the dynamo with a drill at about 2500 rpm it's turning out 27 Volts which seems somewhat high for the voltage regulator to have to deal with

Any opinions ? ? ?

Clive

Oxford UK

m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmm mmmm

[img]https://ec.yimg.com/ec?url=https%3A%2F%2Fipmcdn.avast.com%2Fimages%2Ficons%2Ficon-envelope-tick-round-orange-animated-no-repeat-v1.gif&t=1524777756&sig=r10oMnwxuIl1c4X3nUdMBA--~D[/img] Virus-free. www.avast.com