Which servo motor is more powerful for turning a tight switch?

I want to turn a quite tight and rigid switch from one position to another (and back again) with a servo motor - to switch between two 12V batteries (it is a 300A switch, so it cannot simply be replaced with a less tight one).

The servo motor that came with the starter kit is way too weak to do it. I have seen a number of other servo motors, but none that specifies the power they have... I don't know exactly how much power it takes to turn the switch, but definitely much more than the tiny servo motors I have seen in connection with Arduino.

Obviously I have 12V available (from the batteries), so it could be a 12V servo motor instead of the 5V one that is standard for Arduino. Can anyone refer me to a powerful server motor that could be suitable for turning my tight switch?

Thanks!

elarpa:
I want to turn a quite tight and rigid switch from one position to another (and back again) with a servo motor - to switch between two 12V batteries (it is a 300A switch, so it cannot simply be replaced with a less tight one).

The servo motor that came with the starter kit is way too weak to do it. I have seen a number of other servo motors, but none that specifies the power they have... I don't know exactly how much power it takes to turn the switch, but definitely much more than the tiny servo motors I have seen in connection with Arduino.

Obviously I have 12V available (from the batteries), so it could be a 12V servo motor instead of the 5V one that is standard for Arduino. Can anyone refer me to a powerful server motor that could be suitable for turning my tight switch?

Thanks!

Read about Torque ...
Motor Torque

If you cannot find a motor with enough torque then
consider using gears to reduce speed or a lever and increase torque.

Gears ...
Speed Reduction

Steppers Motors ...
Steppers
.

How much are you willing to pay?

While you could buy such a servo (or, for that matter - a linear actuator might work well, too) - expect to pay a bit of money for it. Alternatively, you could build your own "diy monster servo" (google it) - using a 12V windshield wiper motor, for instance. Doing so would be cheaper, but would require more effort (and may or may not be reliable).

Have you considered using a couple 300A contactors, controlled by 12 volts? Something like:

20A-350A Gigavac Contactor w/ 12V DC Coil

(note - I know nothing about this part, the manufacturer, or the vendor - I'm just showing it as an example)

You could then switch the contactors as needed via the Arduino (and a transistor/mosfet interface). They aren't cheap, but they are likely more reliable than any homebrew method (mechanical or otherwise).

I want to turn a quite tight and rigid switch from one position to another (and back again) with a servo motor - to switch between two 12V batteries (it is a 300A switch, so it cannot simply be replaced with a less tight one).

Why is the switch so tight? Is it an RV battery switch?

Hi,
It sounds like the switch is a circuit breaker, relatively easy to turn off, but harder to turn on.

Can you post a picture of the switch please so we can get an idea of its size.?

Thanks.. Tom..... :slight_smile:

Thanks for your replies. I will study the links you have suggested.

Please see attached a picture of the switch. It has to be very tight in order to avoid overheating (and toasting). 300A is a lot of power...

By the way there is also 220V AC available there if that would enable a servo motor with more power. I just need to be able to control it with the Arduino.

battery_switch_pic.jpg

Have you considered using a couple 300A contactors, controlled by 12 volts?

That is definitely a good idea (instead of mechanical parts). But I would prefer one 'conmutor'/switch (a.k.a. battery switch) instead of two ON-OFF breakers/contactors.

Does anyone know an electrically controllable battery switch without mechanical parts?

Do you have a picture or link to the switch?

Does the switch need to be turned rapidly to avoid sparking and internal melting? If so
you need high torque and rapid movement, which means a big (gear) motor.

Oh and some numbers please - measuring/estimating the required torque and speed is the
first step to do. Unless you go the route of replacing the switch with a contactor (which
makes everything simpler)

Thanks for your input. There is a picture attached to post #5

I am definitely going for the contactor. The motor idea is dead.

But I would like to find a remote battery switch (to shift between the two batteries with just one switch) instead of two contactors...

One changeover control switch (SPDT) can control both contactors (one on with the other off and vice versa) and two SPST contactors wired to such a switch and suitably inter-coupled is electrically identical to a single SPDT contactor. It simply occupies slightly more space and uses two coils. It does have the benefit on having the feature of complete battery isolation if you use a centre-off changeover control switch.

One changeover control switch (SPDT) can control both contactors

Yes, I read about SPDT. But I have been unable to find any at a reasonable price (meaning not more expensive than two SPST contractors). Do you know any?