Fibo motor pulse mods

johnsattuk

There has been some discussion recently about the need for a 5v supply to the pulse circuit used on Fibo motors. I myself have several Fibo's and have solved the problem in the past in various ways. Since most of the positioners/receivers about at the moment only cater for reed switches, I decided to have a look at modding the Fibo motor to a reed switch.

After a bit of investigation, experimentation and choosing the right bits and pieces, it was an easy mod to do. I have modded my motors in use and also my spares.

The attached pics show the mods.

The first pic shows the the bits required.

Drilled gear wheel, drilled to take either one or two magnets, and a couple of lightening/balancing holes whilst I had it on the machine. Some positioners may not accept the double count freq. and/or the total count. Some only count up to 999

Top steady plate grooved to locate the reed a little. Two miniature disk magnets. Reed switch, with suitable wire

The second pic. shows some pre-assembly, showing gear with one or two magnets. and the reed switch with wire attached.

The third pic. shows the assembled motor with a double pulse wheel.

The mods do not drastically change anything, the optical pulse system could be reinstated quite easily, it would only require a bit of black tape over the unrequired holes in the gear wheel, and the optical sub ass. remounted. I don't know of any reason to change back, but the possibility is there.

If anybody wants to mod their own motor, I will help in way I can, just ask

Attached Images

	FiboPulse-0.JPG (149.2 KB, 45 views)
	FiboPulse-1.JPG (147.3 KB, 40 views)
	FiboPulse2.JPG (120.9 KB, 56 views)

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Oldgeezer

_stu_

Hi John,

Did you try to do anything with your v-sec motor? If I recall correctly the cog already has a magnet attached.

CROSSBONES

Is the metal piece in the pic (with the cogs), already in the motor, or is a piece you have added?

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Roiders are like the sun, big, orange, and never stare directly at them

johnsattuk

Hi Stu

Had a little play with it, but don't have or likley to get a receiver with V-Sec protocol, so seeing it as spare parts.

It does have a thin disk magnet on the gear wheel and it uses it a hall effect sensor on the PCB. The magnet did not seem to be strong enough to operate a reed sw. though it was only a handheld test. The hall effect sensor is probably more sensitive as it is powered and amplified.

The gear train is also slightly modified to give an extra 1.5mm room for the disk magnet. I did do a cursory search for similar magnets, but it was probably made to suit.

I used small but strong 'rare earth' magnets which I could fit into the body of the gear wheel .

The gear spins fairly fast and other than balancing it on a M/C the extra weight of a disk magnet might cause extra noise, wear and vibration. The small disk magnets don't add any weight and can be placed quite accurately. I also drilled a couple of extra lightning/balancing holes to compensate a little for the existing slot.

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Oldgeezer

johnsattuk

The 'metal piece' or 'top bearing bracket' is part of the origional motor. I have milled a shallow groove in the top, just to help locate and position the 'reed'. This is not totally neccessary, the first one I tried was OK without the groove but I felt it was an improvement.

The only added parts required, are a 'reed switch' and magnet/s.

The only Machining required is the holes in the gear wheel, bit of care needed, so as not to damage soft brass gear wheel.

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Oldgeezer

johnsattuk

Perhaps slightly off topic, but all to do with the 'Fibo motor'

One of the main faults (IMHO) with the Fibo motor is the lack of limit switches. It is a common fault that the motor is accidentally driven too far, the motor has enough torque to damage the plastic pinion on the output shaft. The pinion typically has teeth broken off and/or the slot in the base is chewed up by the dowel pin, which itself is usually damaged. I believe that there have been some metal pinions made and used because of this. This does not overcome the problem and in fact is likely to cause more serious damage to the motor's innards. I think the standard pinion is able to cope quite well with normal use.

I have seen examples of limit switches on the large diecast gear, which is perhaps the best place for them, but the ones I have seen are a bit 'heath robinson' , and need extra wiring into the motor, also the switches are a bit exposed to the elements.

One of the interesting changes that I noticed on the 'V-Sec' motor was that it had some built in limit switches, they are ingenius in the way they are designed, but a bit basic in function. The switches limit the rotation to approx 2 turns in each direction, but are non-adjustable, this protects the motor from overdriving in an ideal situation, where the dish is free to turn the full amount, but if the dish is restrained by its location, the switches do not work. It would be much better to be able to set any positions, as in most H-H motors.

This is on my list to look at.

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Oldgeezer

Muad'Dib

Hi Johnsattuk,

what is the limit for the original Fibo motor??
gregorian-users shows some examples of the damaged pinion and also the solution (drive limiter).