Quantum Deliver 75% Cost Savings on Generator Hire

Quantum Controls’ client, FCC Environmental, were planning their annual maintenance shutdown for critical service works required throughout their plant processes.  As part of the shutdown, mains power was switched to temporary generator backup to allow for transformer and switchgear works.  As part of the temporary generator supply, the main process air fan had to stay in operation for safe working and operational regulations.

The fan motor is 132KW rated and of DOL starter control, previously FCC have had to size the generator to suit the fan inrush starting current (approx. 1800Amps) as part of the generator power supply scope.  This meant previously a 1250KVA generator was required, and whilst this suited the starting current, it was then way oversized for its nonimal running duty of around 400A depending on site loads etc.

But what could be done?
We suggested that the amount of power required to start this fan could be vastly reduced by using one of our bespoke, multi function and weather proof variable speed drive (VSD) hire panels.  The calculation meant that a generator rated to just 500KVA would suffice not only for the fan starting requirements using VSD, but also the other site loads been used during the service outage.

This resulted in us supplying & installing the equipment, along with a full test and commission of the set up.  The VSD hire panel allowed a 500KVA generator to suffice the requirements, reducing the size by over half and not only saving space on site, over sized cabling, but also hire costs, transport costs, fuel usage etc.

Reducing Generator Loads
Using our in-house expertise, we assessed the options to deliver bespoke support to their client.  To allow for the starting current peak transient, generators needed to be sized to at least 7 to 8 x the motor FLC / power on DOL operation and 4 to 5 times on star delta. By using a VSD system, the motor can be accelerated to full speed in most instances within the FLC rating.

This is a costly way to start a motor and even more so when on a generator load, by switching from DOL or Star Delta to VSD control on such motor load applications, huge cost savings can be seen
and well as large logistically issues for both siting and transportation of the equipment required.

Our Expertise Lead To Cost Savings
Saving the client money and offering a greener option was Quantum Controls main aim.

Through extensive research and skill, the team added a variable speed drive (VSD) to control the full load of the motor’s starting and running point.  This option offered a power factor near as 1.0 to the motor load.  The VSD accelerated the motor and fan load with excess starting/acceleration current to the motor full load current.

From this, the team calculated: 132KW power required at 415V, 1.0 PFC through VSD control, KVA rating considering losses for harmonics generated from a six pulse system into the generator then an 500KVA generator set would be suitable for the tests.  We supplied an 500KVA generator to the client with a 132KW VSD hire panel.  Tests were completed as required and within the power limitations from their selections accordingly. This led to several benefits for the client, including;

• Benefit 1: Saving on rental costs, unnecessary additional transport costs and space on site needed to house the equipment.
• Benefit 2: Power reduced from 1250KVA down to 500KVA, with the added option of the 500KVA being more suitably selected to the full load power/ current required.
• Benefit 3: Fewer fuel costs/carbon losses, not only on start-up but on running currents.  The drive offers optimal power/torque control and reduces loads on the generator.  The client was delighted by the results.

Cost-Effective and Green – The Ultimate Solution!
The cost and energy/carbon emission savings made the additional VSD hire costs neutral to the project. The VSD option saved more per week than the VSD hire price alone, making it much more
cost-effective, not to mention a greener option for the client.

If you’re looking to save money with our Rental Services, speak to one of our experts on 0330 900 247.