1-1.5 KW Vacuum cleaner motor control.

Hi. So Im building this project to remotely control my vacuum cleaner with a couple of nanos and nrf24l01 modules. I have figured out the code and wireless part. Now I need to find the best way to switch on and off my vacuum cleaner Festool CTL MIDI 110V and power consumption 400-1200W. https://goo.gl/esolAV Ive tested (with multimeter) the power leads to the actual motor and it shows ~111-113Volts and at least ~13A spike on startup and then it settles at around ~9.3A. Blocking the suction hose sounds like you are putting more load on the motor but actually power seems to drop to ~8-5Amps (go figure :confused: ).

Ive tried using "crydom" CWD2425P SSR(no heatsink) http://www.farnell.com/datasheets/1902549.pdf and it seems to work ok for a short period of time, however the relay seems to get very hot after few minutes of operation. And I dont have enough room for a chunky heatsink inside the vaccum. So now I`m thinking of using a mechanical 30A 5V relay http://www.ebay.co.uk/itm/5V-30A-High-1-Channel-Relay-Module-Level-for-Arduino-DSP-SLA-5VDC-SL-A-/161947767888?hash=item25b4d6d450:g:ocQAAOSwL7VWmMIu.

If anyone has any thoughts please share :)

The relay should work fine indeed. A SSR @ 10A might indeed produce heat. Which version did you use?

dainazinas: Blocking the suction hose sounds like you are putting more load on the motor but actually power seems to drop to ~8-5Amps (go figure :confused: ).

But it does not ;) All the resistance (mechanical) the motor has to overcome is air. And while spinning it forces the air out of it's way. But normal it sucks in new air via the hose. But if you block the hose it can't suck in new are (only leakage) so new the blade spins in a vacuum aka there is less air. Less air = less air resistance = less power needed :)

septillion: The relay should work fine indeed. A SSR @ 10A might indeed produce heat. Which version did you use?

I used a |186x250

And thanks for for your opinion mr septillion :)

As for the "clunky heatsink inside the vacuum" - typically, those things have some sort of junction box where all the wires come together etc. You should be able to screw the relay to the side of the box which will act as a heatsink.

dainazinas: I used a |186x250

And thanks for for your opinion mr septillion :)

the spec gives dissipation graphs.

Some heatsinking is required , if you can get the heatsink in the airflow it could be fairly small.

and power consumption 400-1200W.

Are you trying to speed control this or just use on off ? It can make a difference to dissipation. A controller with zero voltage switching would help here.

EDIT i looked at the spec for that vacuum, it does say 400 to 1200 W, that implies some speed control and may well affect the performance of using an ssr to control it..