Ador Welding Ltd: e-Weldone Newsletter

REDUCE ENERGY BILLS BY USING WELDING INVERTERS WITH IN BUILT ACTIVE AND PASSIVE FACTOR CORRECTION

INTRODUCTION:

Companies often overlook the potential for saving costs in utilities like electricity. Many people do not realize that the energy bill they are paying for also include significant amount of unproductive (reactive) power instead of the power they actually utilize (active power) during welding operations.
Although Inverter welders are light weight compact machines and are energy efficient, not all Inverter welders can be “more cost efficient” with respect to energy saving. Hence it is important to define what “More Cost Efficient” means. This article will discuss about the electrical running costs of inverter welding machines being used and how active and passive power correction can provide MORE reduction in energy cost. We will also define what “More Cost Efficient” means for ADOR equipments.

HOW EFFICIENCY AND POWER FACTOR AFFECT THE RATING OF A WELDING MACHINE.

EFFICIENCY:

Efficiency is the ratio of output power to input real power. Efficiency directly affects the cost of energy. A machine with a higher efficiency converts more of the power it draws from the input line, which in turn reduces the amount of wasted energy (given off in the form of heat). Efficient machines run cooler, draw less power, and cost less to operate.
It is important to not confuse the measure of a machine’s “apparent power” (kVA: Input Amps x Input Volts), with the “real power” (kW) the utility company charges for. The “real power” takes the machine’s power factor into consideration. Higher the efficiency lesser the power consumption for delivering the same output power.

REDUCED POWER CONSUMPTION MEANS:

Reduction of power consumption lowers energy/demand charges from utility companies, providing substantial cost savings
Incentives are offered by utility companies to adopt higher end technologies that require less energy demand
Reduce the chances of overshooting the max demand (as sanctioned/allowed by the electricity suppliers) and thus reduces the risk of penalties usually charged due to overshooting above mentioned allowed max demand

POWER FACTOR:

The combination of increasing electrical loads and scarcity of electricity has resulted in more emphasis on electrical power factor. Power factor is defined as the ratio of real power to apparent power. Not all of the current that is drawn by a machine is used by the machine.
Higher power factor indicates that a higher percentage of the apparent power drawn from the power line is used by the machine. A rating of 0.95 means that 95% of the apparent power is converted to real power. A poor power factor level requires a higher current to be drawn to perform the same amount of work. Optimizing power factor can reduce the load on the electricity distribution system. This simple solution increases electrical capacity, without the cost of additional infrastructure.

INCREASED POWER FACTOR MEANS:

Improving power factor increases capacity of electricity utilization for a given installed power in the factory or at the project site
Less current is required for the same reliable output
Reduced stress on distribution equipment leads to longer life of equipment.

There are two general causes of poor power factor, one is reactive loads and another is electronic power supplies. Poor power factor caused by reactive loads, such as big motors, transformers etc. can be corrected by adding a capacitor in parallel to the load. However for Electronic power supplies, (for example, inverters) power factor cannot be corrected by adding capacitor in parallel. Hence in order to improve power factor, the machines have to be designed with power factor correction (PFC).

HOW TO IMPROVE POWER FACTOR:

For three phase inputs, passive power factor correction is the best method for improving power factor. The other alternative is active power factor correction, which is normally used for single phase input supply machines. As the names imply, the passive approach uses passive components and the active approach uses active components.

The advantages of passive PFC are:

Passive PFC is less complex and more reliable.
Passive PFC has lower losses and higher efficiency.

All three phases of ADOR inverters e.g. CHAMP 400, CHAMP T400 and CHAMP MULTI 400 are designed with passive power factor correction.

Active Power factor correction is done by an active PFC switch which is basically an AC/DC converter, which controls the current supplied to the welding inverter via a “Pulse Width Modulation” (PWM). This power factor correction stage acts as DC pre-regulator stage, to which wide AC input voltage range supply can be applied and it will provide constant regulated DC output voltage. This DC regulated voltage is further applied to welding inverter as shown in the figure. Hence practically, a single phase welding inverter with active power factor correction can work on wide input supply range of 90Vac to 270Vac.
Single phase inverters of ADOR, particularly CHAMP 165, CHAMP 203 andCHAMPTIG 163 are designed with active power factor correction, which can work from 90Vac to 270Vac and has 0.98 power factor through out the welding load.

COMPARISON:

If we compare the Single phase inverter without Active power factor correction and Inverter with Active power factor correction at various welding current, then we can observe the saving on energy bills with higher power factor and efficiency is substantial.
Following tables give the details of input power measurement which clearly indicates that, machine having higher power factor draws less input current and also have higher efficiency at that particular load condition.

Table 1:

	INVERTER WITHOUT POWER FACTOR CORRECTION Input Power Measurement in MMA mode during actual welding :-							Conventional Inverters 160A / 200 A
								Conventional Inverters 160A / 200 A
SR.	Electrode	Output	Output	Input Current	INPUT KW	INPUT KW	PF	EFFICIENCY %
No.	Size	Current	Voltage	(A)	INPUT KW	INPUT KW	PF	EFFICIENCY %
		(A)	(V)
1	2.5MM, 6013	70	19	11.15	3.11	2.02	0.65	65.84%
2	3.2MM, 7018	120	24	24.39	5.61	4.04	0.72	71.30%
3	4.0MM, 7018	160	28	32.96	7.58	5.91	0.78	75.80%

TABLE 2:

	INVERTER WITH ACTIVE POWER FACTOR CORRECTION Input Power Measurement in MMA mode during actual welding :-							ADOR INVETERS CHAMP165/ 203
								ADOR INVETERS CHAMP165/ 203
SR.	Electrode	Output	Output	Input Current	INPUT KW	INPUT KW	PF	EFFICIENCY %
No.	Size	Current	Voltage	(A)	INPUT KW	INPUT KW	PF	EFFICIENCY %
		(A)	(V)
1	2.5MM, 6013	70	19	7.2	1.69	1.48	0.879	89.86
2	3.2MM, 7018	120	24	13.9	3.24	3.1	0.96	92.9
3	4.0MM, 7018	160	28	23	5.1	5.02	0.986	89.24%

ENERGY COST:

Following calculations show the energy saving of Inverter with active power factor correction in comparison to Inverter without power factor at welding current of 120A. In this case arc time considered is 4 hour per day and cost of one kWh unit as Rs.7/-

Taking the power parameters from above two tables at 120A:
Energy saved per day	= (4.04-3.1) kWh x 4 hr	= 3.76 kWh / day
Energy cost saved per day	= 3.76 x Rs. 7.00	= 26.32 Rs./ day
Energy cost saved per year	= 26.32 x 300days	= Rs.7896 per year

If 100 such welding inverters are being used at various shop floors inside the given factory or at project site, the total annual energy saving cost will be Rs 789,600/- which is very significant. This is what “MORE COST EFFICIENT” means for the ADOR welding Inverters

As illustrated above, high-efficiency welding machines produce substantial cost savings. ADOR inverters consistently achieve higher efficiency, and thus, lower the cost of energy.
Hence, investment made in ADOR Inverters pays for itself with the money saved by reduced energy consumption.

Following table give the power ratings of some of highly efficient inverters offered by Ador Welding Limited for various welding process.

Sr	Parameters	CHAMP 165	CHAMP 203	CHAMPTIG 163	CHAMP T400	CHAMP 400	CHAMP MULTI 400
1	Welding process	MMA	MMA	TIG/ MMA	MMA	MMA	GMAW/ MMA
2	Welding Current Range (A)	10-160	10-200	5-160	10-400	10-400	10-400
3	Power supply phases	1 phase	1 phase	1 phase	3 phase	3 phase	3 phase
4	Input Supply Voltage (Vac)	90-270	90-270	90-270	415 +/- 10%	415 +/- 10%	415 +/- 10%
5	Efficiency	89% max	89% max	89% max	89% max	84% Max.	84% Max.
6	Power Factor	0.98	0.98	0.98	0.95	0.9	0.9
7	Type of Power factor correction	Active	Active	Active	Passive	Passive	Passive

CONCLUSION:

Per unit costs and the gap between supply and demand of electricity are ever increasing. More efficient Inverter welding machines offer the benefit of bigger savings in energy cost due to electricity alone. More numbers of welding machines and welders can be deployed on the given installed/available power by using these ‘more efficient’ welding machines, which will finally increase welding productivity. Thus it is imperative for every user to switches over to such ‘More Efficient welding machines’.

Please contact us at cmo@adorians.com or visit us www.adorwelding.com to know more about our range of inverter welding machines and how you can reduce your energy bills.

For further details, please visit us www.adorwelding.com or write to us
cmo@adorians.com