voltage spike suppression ? - spikes lower

[glowingturnip]

Hi,

Just wondering if anyone uses anything for suppression of voltage spikes in mains voltage ?  Specifically I'm looking at spikes *lower* in voltage.

I do my imaging at our small farmhouse in Spain.  The utility supplies are poor to say the least, we have water that is delivered sporadically which goes into a deposit which we then pump round the house, and we have single-phase low power electric supply which can trip even if say the washing machine and dishwasher are on at the same time, and when the water pump kicks in all the lights dim.  I run my rig off a cable from the mains.  So basically, if someone flushes a toilet, the voltage drops and I can see it in my guiding graph !

I'm just wondering if I can put some kind of Belkin surge protector gizmo between mains and mount that would have capacitance in it to protect against temporary drops in voltage ?

Cheers

[gajjer]

Hi Stuart

from what you say, it sounds as if your mount is powered from a mains adapter. I would suggest that you have something like a 12v battery that you keep charged from the mains. Much less succeptible to mains fluctuations.

It would really help to know more about how things are powered.

hope that helps.

cheers

gaj

[SnakeyJ]

Stuart, I think Gaj is on the right track here - I used a small (1500KVA UPS) in my own observatory that gave a regulated 240AC to my DC transformers and everything bar the dehumidifier and hair dryer.      Though the UPS was borrowed from work.      I think leisure batteries, charger and perhaps some PV to take advantage of the Spanish sun would probably give maximum autonomy.

[glowingturnip]

thanks guys,

I'm running it as mount to  mains-to-car-cigarette-lighter adapter to extension cable to mains.

I do have a small standalone battery that the mount can run off, but to be honest I think I'd prefer the relative reliability of the mains supply - power cuts are still pretty rare and would be in the daytime, it's really the little blip lower in the voltage slowing the mount motors down that I'd want to protect against for that split second.

[Horwig]

I'm with Gaj as well on this one. Use the battery to store power, rather than as a supply in its own right. That is, run the mains to 12v adaptor to the battery and mount together, so the 12v from the battery fills the dips in power.

Huw

[Uranium235]

I use a surge/spike protected socket into which I plug the 4-way 25m extension lead. Reason being the freezer is in the same room as my power outlet, and when the motor kicks in it can (and does) cause spikes... thats the reason you never see a fridge in a recording studio either. The bench supply I use also does some smoothing, and (touch wood) Ive never had a problem with it.

[Alien 13]

Mains is "dirty" at the best of times and adding filters does not realy do much to clean it up and if  not done properly can make it worse, I too would opt for a battery/smart charger option if mains is required too then you could power an inverter off the battery.

Alan

[Physopto]

The only type of UPS that are of any real use are  the types that are on all the time. In essence they completely segregate the mains from the item being powered. They are costly and relatively inefficient. If you need them for prolonged blackout situations then they require a relatively expensive battery bank installed. There is a type that is commonly used, but on a brown out or other type of voltage drop, they will change over to battery powered supply. BUT there is a miniscule loss of voltage  and usually a small spike in the  voltage supply. They are getting better but an oscilloscope will show up the proof.

On equipment such as a computer it really is not  good to take the chance. Also on a mount it is possible to lose the positioning even if the voltage loss is for a few milliseconds. The better UPS of this type are still expensive. The end cost is  down to how long the system can run for under load conditions and that depends upon how much standby battery power is fitted, ( how many installed batteries in the unit).

As you say the problems are not so dire then I suggest you GO BATTERY. Much cheaper and will completely eliminate any voltage spikes from the mains. The battery can be left on standby charge all the time and so will last a long time. It will never be partially discharged so will be in the best condition all the time . Just use an intelligent type charger. CTEK or some such are really good. I never use the mains at all to run equipment, only from a battery. A good leisure battery is all, you need.

As the voltages are low after the charger, it is also the safest method going.

Derek

[gajjer]

Hi again Stuart

I haven't put a oscilloscope current probe on my NEQ6 so I don't know what the current looks like, but I did once put a current clamp meter on it. It was a long time ago but I think it was about 1Amp while chugging in one axis.

I would guess that the peak current gulped would be higher than this since it's driving stepper motors. The battery solution provides a good source of power that will easily ride out any gulps that your system demands. I use a small battery charger to keep it topped up. ( I think it was a Maplin lead acid battery charger that drops out when the battery is fully charged ). I don't know what your cigarette lighter supply is like but the chances are it's a switching mode supply and will have very little hold-up in the event of a short mains drop out. It may be that there is enough voltage to keep the electronics running but not the motor.

The only way to be sure would be to capture the voltage waveforms during an interrupt. Good luck with that one!

For me, and trust me, I am an electronics engineer, I wouldn't run my mount without a battery next to it.

Good luck.

I hope you find a solution.

cheers

gaj

[glowingturnip]

hmm, food for thought (although I'll admit some of the details are beyond me !).

So could I power the mount from a battery, that itself is plugged into a charger - so that the battery doesn't become uncharged, but any mains interruption will be covered by the battery ?  I think the battery I have has a switch though, you can either use it or charge it, not both.

Or could I have the mains supply and the battery supply in parallel somehow ?

[Physopto]

That is the whole point of what we have been saying. Use a battery with the charger connected at all times. The only mains is the connection to the charger.

Then the battery powers the mount and all ancillary equipment. All 12 volt if that is what the mount requires.

Derek

[glowingturnip]

cool, will try that, thanks all