Power factor of motor with VSD?

AI Thread Summary
When a motor with a full load power factor of 0.8 and a starting power factor of 0.3 is equipped with a Variable Speed Drive (VSD) rated at a power factor of 0.95, the starting power factor remains at 0.3. The VSD's power input is designed to maintain a power factor of 0.95 through a power factor correction circuit. However, the DC reservoir capacitors separate the motor load's power factor from the main supply's power factor. While the VSD can improve efficiency, the motor's inherent power factor does not change. The VSD must be appropriately rated to manage the reactive VAR of the motor load effectively.
Martinz
Messages
1
Reaction score
0
TL;DR Summary
Power factor at the motor with VSD
If I have a motor with a full load power factor of 0.8 and starting power factor of 0.3 and I install a VSD to run it with a datasheet power factor of 0.95, will the power factor during starting be 0.3 or 0.95? And at full load?

Cheers!
 
Engineering news on Phys.org
Welcome to PF.

The power input to the VSD should be maintained at 0.95 by a PF correction circuit that controls the switching input rectifier.

The DC reservoir capacitors isolate the PF of the motor load, from the PF of the main supply.

The motor PF will not change, but the VSD must be rated to handle the reactive VAR of the motor load.
 
Reply
  • Like
Likes Delta Prime, Averagesupernova and russ_watters

Thread 'Following up on the recent thread about Earth Resistance measurements'

I have recently moved into a new (rather ancient) house and had a few trips of my Residual Current breaker. I dug out my old Socket tester which tell me the three pins are correct. But then the Red warning light tells me my socket(s) fail the loop test. I never had this before but my last house had an overhead supply with no Earth from the company. The tester said "get this checked" and the man said the (high but not ridiculous) earth resistance was acceptable. I stuck a new copper earth...
View full post »
Thread 'Electromagnet magnetic field issue'

Thread 'Electromagnet magnetic field issue'

Hi Guys We are a bunch a mechanical engineers trying to build a simple electromagnet. Our design is based on a very similar magnet. However, our version is about 10 times less magnetic and we are wondering why. Our coil has exactly same length, same number of layers and turns. What is possibly wrong? PIN and bracket are made of iron and are in electrical contact, exactly like the reference design. Any help will be appreciated. Thanks. edit: even same wire diameter and coil was wounded by a...
View full post »
Thread 'Beauty of old electrical and measuring things, etc.'

Thread 'Beauty of old electrical and measuring things, etc.'

Even as a kid, I saw beauty in old devices. That made me want to understand how they worked. I had lots of old things that I keep and now reviving. Old things need to work to see the beauty. Here's what I've done so far. Two views of the gadgets shelves and my small work space: Here's a close up look at the meters, gauges and other measuring things: This is what I think of as surface-mount electrical components and wiring. The components are very old and shows how...
View full post »

Similar threads

Having difficulty increasing my load power factor above 0.95
Replies
12
Views
3K
Reducing AC inrush current in this setup
Replies
15
Views
3K
Electric motor - variable torque vs speed
Replies
13
Views
2K
Alternator run at zero power factor lagging
Replies
2
Views
1K
Sizing an Isolation Transformer for a DC Power Supply
Replies
8
Views
2K
VSD for induction motor maximum current
Replies
1
Views
2K
Help in understanding current ratings of wires from datasheets
Replies
10
Views
2K
How to make the power factor of induction motors be a leading power factor?
Replies
3
Views
2K
Dynamometer output readings for my moped
Replies
2
Views
1K
Optimal Motor Power for DIY Cat Waste and Litter Device
Replies
5
Views
1K

Hot Threads

Recent Insights

Back
Top