Direct driven fans fans of all types have traditionally been driven by belts.
Belt drive fan with vfd.
Qualitytime civil environmental 15 mar 16 18 02 vfd s need filters and line reactors to prevent harmonics backfeed onto the line side.
Today most standard nema premium efficiency motors are designed with characteristics that enable use with vfd s on variable torque loads such as the majority of fan applications.
The marley geareducer gear drive offers a more efficient alternative that provides energy installation and maintenance cost savings.
Efficient synchronous motor technologies that always require vfd control such as permanent magnet and switched reluctance motors.
Both an ecm and a vfd control motor speed by manipulating the frequency and voltage of electricity supplied to the.
While both belt and direct drive fans have been around for a long time the mainstay fan for most industrial fan applications under 250 hp has been the belt drive fan.
Well if your fan wheel is perfect at 1760 rpm it would ramp up great with a vfd.
And of course you need to know the input frequency of the motor and a few simple ratios.
A vfd is a great solution when a flexible fan speed solution is required.
Belt driven is not a problem but you need to check the motors to see if they are compatible with vfd.
One uses a variable frequency drive and the other makes adjustments based on calculated sheave ratios.
On belt driven fan applications a vfd is also useful for simple speed changes.
A high inertia impeller fan can be started with a vfd using a much smaller motor than would be otherwise required to start the same fan across the line.
Belt drives are often employed in cooling towers with lower horsepower requirements.
Direct drive fans typically work better when you are trying to vary the speed of the fan with a vfd variable frequency drive or a potentiometer rheostat variable speed controller.
Controlling fan speed on a belt driven fan.
Costs by eliminating belt transmissions further cost reduction due to lower inrush current.
Belt drive allows you to be much more compact on the big equipment not going to have a direct drive 15 horse blower motor spider mounted to a fan scroll.
The programming of some vfd s are complex and can be overwhelming.
Plug plenum fans can end up high rpm the plenum cabinet you install them inside would get a couple few feet longer with direct drive.
These motors will be labeled as either inverter ready or inverter rated depending upon the motor manufacturer.
Like a gear drive the belt drive does not require a variable frequency drive vfd.
Not all motors will last with vfd drive.
Because of the fewer parts involved they can often be more compact in design.
With the growing acceptance and affordability of vfd motor controllers direct drive fans are increasingly finding their way into mainstream industrial fan applications.
The integration of variable frequency drives in hvac units are becoming required by code.
With a belt driven fan there are two ways to control speed.
