6 volt motor power source

I'll have you know I had a haircut today and I look quite lovely.

It's a post without any real context.

What the OP may have failed to realise is that his previous posts on his micro circular saw may not have been read by anyone now posting to this latest request. Even if some of us did read the previous posts there have been many hundreds of other posts to this group since and remembering any real details from even a few days ago is suspect.

Previously a 3V motor taking 3W under load was being considered with many suggesting that it was under powered. It now appears that its a 6V motor but with no specification its hard to give any meaningful answers.

Yes it may run with a 5V supply and yes it may run with the lead in the link but if the motor takes more than 1A under load then the battery will/may be limiting the current

The OP is attempting to "design" a circular saw for young children to cut no more than a 2mm wooden coffee stirrer with a 30 to 60mm blade so possibly doesn't need to go to the level/power of a Dremel nor need to go to 80W motors as used on some DIY "hobby" circular saws that can cut

Actually, that cable is no good. The power bank outputs its charge thru the USB A port.

Can we start again and ask what is the purpose of this exercise?

Is it to make a working tiny model wood cutting saw as a hobby project or to do something to a large number of small thin pieces of wood?

Can it run off mains using an adaptor?

I want to build a box that will house a circular saw blade that will be fully enclosed within the box. However, there will be an slot into which a coffee stirrer can be slid laterally. If this unit runs on battery power the charge should be able to make...perhaps a 100 such cuts. I hope thats enough info.

Using a multimeter, measure the current flow in the motor while it is cutting the coffee stir stick. Maybe it's 6V @ 1.5A using the six volt (four dry cells at 1.5V) you've been using so far for testing.

Running a 6V motor at 5V from the power pack, will reduce speed and power output.

Power packs, as we see them advertised online, are usually

They expect mostly resistive loads. Not the inductive load of the motor. And the power pack would also be limited in the amount of capacitive load it could drive (not an issue in this case).

Summary:

2) You can measure the current flow, using four dry cells as a power source for your motor, while it cuts a coffee stir stick. Dry cells are 1.5V each, four of them 6.0V, and suitable for a quick check of performance.

4) Power packs, as normally supplied, would not be an ideal power source. Five NiCd cells at 1.2V each would give 6V and would be rechargable like the power pack. NiCd is less dense than the Lithium in the power pack. Perhaps five NiMH cells at 1.2V each would be a solution, assuming they can provide the amperage measured in (2).

A multimeter has a 10 amp current flow range, but the meter is not intended to make "long time period" measurements. Heed the duty cycle printed on the meter, if measuring 10 ampere values of current. Lower currents, you can measure those for a longer time without the shunt inside overheating.

Batteries have specs.

Tenergy D 10,000mAh NiMH Flat Top Rechargeable

Quick Charge: 2000mA for 7 hours

I think Martin was hinting at ?why??.

Whilst the ?why? PF your project is in some senses irrelevant, it might influence the quality of advice that you get. If it?s purely to make a ?child-safe? electric toy saw there might be better ways to achieve what you want. If you have a different motive for this project then again it might be useful to share it as there may be other approaches that you?ve not considered.

You currently seem to be determined to make an underpowered, under-speed circular saw for no good reason and your requests for information suggest a degree of mechanical and electrical inexperience. Nothing wrong with an ?oddball? project just for the heck of it but you?ll get better advice if you explain WHY as well as WHAT you?re trying to make.

Tim

I should change tack and go with a power adapter, I think.

Thanks, I did look back a long way and can see an attempt to make a small saw-bench. I couldn't see any reference to young children.

Have you measured the consumption yet ? While sawing the coffee stir stick.

Test Source -->---------X Multimeter Amps X--------X motor X---+ | Test Source --

No, run the motor from a battery, or alternatively from a bigass power supply. I'd use a battery and charge it later.

Bill

He won't mention that because it's quite illegal to chop up children.

Bill

Cutting matchsticks requires very little power. You might even get away wit h a few amps at 5-6v. If you're trying to cut up small children you'll have bigger problems than picking a battery. Much bigger problems.

BTW I can't help thinking it'd be easier to use a simple chop/cut mechanism , basically mildly serrated tinsnips inside your box.

NT

ulation-for-dc-motor

And to take it a step further, you gotta consider what you want the thing t o do when the motor is kept stalled, as it will be by children. The choices are the PSU trips out or the motor burns out or catches fire. They key bit is that you make the decision which you want & design it so it does that e very time.

Motors take far more current stalled than running unloaded. You don't need to allow for much more than stall current in any situation. Stall current i s determined by dc resistance, so it's easy to measure resistance & calcula te the stall current for any motor you have.

NT

What is the power of the motor and what is it for. Most usbpower sources have limited current available. I know some of the usb fans you could get for keeping you cool would not power from my old pc. Brian

IIRC its a dimension somewhere = 60mm Mabuchi made/makes can motors 280,300,400,480, 540, 600 and something larger IIRC.

there were also even smaller ones for toothbrushes etc. 90% of all appliances use these motors. And cars for window winders etc.

There was another, better manufacturer down at the cheaper end - Sagami

here is some data on them applicable to model aircraft/

Good gentlemen of this group. I fully admire and respect your knowledge of all the topics that you have put before me in the past week or so. However, I am a bit long in the tooth to take on this jungle of learning. So, given what my basic requirements are A powered saw blade that will be required to cut: coffee stirrer sticks choc ice sticks dental pallet sticks ('say aah!) and the occasional 6mm square stock. (all soft woods)

Could you recommend to me a mains adapter and a motor (x volts to x+y volts, (f*ck knows what) amps, etc etc.

As a reward, I will tell you what has set me down this road. I think some of you will find it interesting. And some of you will think, Pfft!

Also, I will give you an idea for an electrics project that will require ALL of the knowledge you have written about to me. Of course this project will be far too difficult for me but might be an interesting challenge to a few of you. Actually just had this idea today.

Anyway.