Fan speed control

[Simon Butler]

I need to drop the speed of a 4kw 3ph fan motor from 100% to 10-15% with a 230v signal.
Is there a cheaper way of doing this other than buying an expensive inverter with lots of features that I don't want?

Simon.

[D.D.KORANNE]

CHECH WITH CAREL OR DIXEL FAN CONTROLLERS FOR THE REQUIRED MOTOR CAPACITY . HOWEVER TO OPERATE THE 4 KW MOTOR AT 10 / 15% OF ITS RATED SPEED WILL BE VERY IN-EFFICIENT WAY . BESIDES FAN SPEED CONTROLLERS FOR CONDENSER CAPACITY CONTROL , TRY A HEAD PRESSURE CONTROLLER VALVE ( SPORLAN etc)

[sachin230]

for what application

[chemi-cool]

Thats a big fan motor, I would check on pressure controlled frequency converter.

Not cheap compare to the small fan speed controller but will do the job much better.

[chilliwilly]

Why do you need to drop the speed only 15%? And what is the 230 v signal for? Is there already a VVF drive controling the fan?

[mbreward]

Hi Simon
Inverter drives are not always expensive, try www.inverterdrive.com. The basic models do not have a lot of features any more. We use Parker SSD drives which are very simple to set up & can be programmed for analogue or digital signals.
Can you explain what the fan is for, is it condenser pressure control or another fan
Slowing a fan down to 10-15% speed is not a good idea as the motor depends on airflow to keep it cool, a rule of thumb is not to slow an induction motor to below 30% speed to prevent overheating unless additional measures are taken to prevent overheating. Although we have not had problems slowing some down to 20/25% speed

Can you give us more information & we will try to help

Mark