research report: tested: inverter welders€¦ · tokentools 142 and the $539 cemont colt s3200 and...

Cash-strapped farmers in the market to buy aportable welder could save almost 60 per cent on theprice of a new unit.

In an Australian first, this exclusive FarmingAhead Research Report shows one inverter welderthat cost just $308 offered a viable low-costalternative to the more expensive brand-name unitson the market.

But for farmers willing to invest more money inan inverter welder, several excellent machinesoffering a range of functions were identified.

Helping keep costs lowKondinin Group engineers said the results were

excellent news for farmers battling successive poorseasons and those keen to reduce their costs bycompleting fabrication and repairs themselves.

The results also showed product price was noguarantee of performance.

Farmer demand sparks tests Members’ calls for performance data on inverter

welders prompted Kondinin Group engineers totest 13 popular inverter welders in a bid to helpfarmers reduce their costs.

One portable inverter welder at just$308 offered a low-cost, entry levelunit, suited for farmers who mightbaulk at the cost of a $1000 unit.

Engineers tested the BOC Inverweld 110, BOCSmootharc 130, CEA Rainbow 150, Cemont ColtS3200, Cigweld Transarc 131i, Esseti 150CS,Euroarc 140, Fronius 1400, Kemppi Minarc 120,Lincoln Invertec V145S, Migomag 155 DCI,Tokentools Miniarc 142 and the TWM IN2500.

R E S E A R C H R E P O R T :T E S T E D : I N V E R T E R W E L D E R S

KONDININ GROUP

[email protected]

JoshGiumelli

Ben

Whi

te

Lightweight inverter weldersoffer flexibility and portabilityin a small package.

Prices range from $260 tomore than $1000, so considerall options carefully.

Using microprocessor control,inverter welders take thepain out of using difficult,sticking electrodes.

Hot-start functions oninverter units make strikingan arc easier than traditionaltransformer welders.

While inverter welders can beused as tungsten inert gas(TIG) welding power supplies,some are more suited to thetask than others.

Inverter welders are nowsafer to use with generatorsand long extension leads.

A t a g l a n c eInverter welders are a revolution in technology, giving farmers the option of a lightweightand efficient tool to repair machinery at an affordable price. In this report, Farming Aheadwriter and engineer Josh Giumelli along with fellow Kondinin Group engineers Ben Whiteand Tim Andrew respond to member feedback and present the results of on-farm tests of13 inverter welders to help separate the tools from the toys.

16 Farming Ahead February 2007 No. 181 www.kondinin.com.au

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(c) Farming Ahead

‘Heat’ put on weldersMost machines tested were easy to use. The main

downside was the price, with some units costingmore than $1000.

But Kondinin Group’s engineers discoveredseveral cheaper inverter welders — such as the $308Tokentools 142 and the $539 Cemont Colt S3200 andthe $324 BOC Smootharc 130 — proved capable.

Yet buyers need to be careful as the small andcompact $260 TWM IN2500 was completely uselessand could only just run a 2.5-millimetre electrode.

Kondinin Group’s independent testsshowed how inverter weldersworked using a range of weldingelectrodes commonly used on-farm.

All other welders tested could run 3.2mm and4mm electrodes, although some lower-rated

A revolution in weldingInverter technology has revolutionised stick or

manual metal arc welding (MMAW) by providing amore efficient and versatile welding power source.

At less than one-tenth the weight and about twice the efficiency, inverter welders can be carriedwith little effort and run using extension leads or generators.

According to manufacturers, sales of traditionalheavy stick welders have fallen dramatically inrecent years as inverter-based units have becomecheaper. Low-cost imported units from China haveplaced pressure on established brands, forcingdown prices.

In addition, inverter welders offer the versatilityof direct current (DC) welding rather than thelimited alternating current (AC) welding fromheavy transformer units. DC tungsten inert gas(TIG) welding also is possible with most of thewelders tested.

Portability has convenience benefits:Welders fitted with a shoulder strapand a carry handle were the mostconvenient units to move about suchas the Kemppi Minarc (left). While theBOC Inverweld 110 had a handy strap,it lacked a handle (right).

RESEARCH REPORT:TESTED:

INVERTER WELDERS

Plugs and leads: Most welders werefitted with a 15A plug (below, left)but some had 10A plugs eventhough they could draw more than10A. Operate portable inverterwelders with 15A-rated extensionleads to reduce voltage losses.

17Farming Ahead February 2007 No. 181 www.kondinin.com.au

Big and small: Kondinin Group tested 13 portable inverter welders to gauge how well each unit worked, suitability for on-farmapplications and value for money. The smallest inverter welder tested was the TWM IN2500 and the largest was the LincolnInvertec V145S.

Test equipment: Group engineers used a DC clamp meter tomonitor output an input current during tests.

Phot

os:

Ben

Whi

te

The drought has increasedpressure on farmers to reducetheir costs but there are some‘toy’ welders on the market thatperform poorly and are unsuitablefor farm conditions.

The 4mm E4113 electrodes tested the welders’capacity to operate a large diameter electrode, withall but the TWM IN2500 passing the test.

But penetration was poor with many units moresuited to 3.2mm electrodes.

Engineers also measured the welders’ maximumcurrent draw with 4mm electrodes. Tests werecarried out using a 10-metre, 15A extension lead, as in most situations welding units are operatedwith some form of extension cord.

Limited voltageBecause air is a poor electricity conductor,

a welder needs a high initial voltage to enable thearc to be struck between the work and theelectrode. This open-circuit or no-load voltage islimited to 110V DC or 80V AC under Australiandesign rules.

After an arc is struck, it travels across the moltenpool of metal and requires a far lower voltage tomaintain it, usually 20–30V.

Some units such as the Esseti 150CS, LincolnInvertec V145S and Kemppi Minarc 120 were fittedwith voltage reduction devices (VRDs). These arerequired for mine-site safety as they lower theopen-circuit voltage to a safer level of 35V or less.

When the welder senses a load with a resistanceless than a certain level (often 200 Ohms) thevoltage is increased to help start the welding arc.

A load with higher resistance would indicate the current might be flowing through the operator instead.

The price of safetyWhile VRD safety benefits are obvious it

increases the welder purchase price and can makesome welding electrodes more difficult to start.

machines struggled to find full penetration with larger 4mm rods. Generally, an output of 140A or more is needed to operate a 4mmelectrode successfully.

Staying powerAll welders, whether they are stick, metal inert

gas (MIG) or tungsten inert gas (TIG), are sold witha rated duty cycle.

The duty cycle is written as a rated level of outputcurrent and a percentage, which is a proportion oftime the welder can hold the output current at therated level. A welder cannot operate indefinitely athigh outputs without being damaged due to heatproduced inside the transformer.

Duty cyclesSome welders are more heavily constructed and

have better internal cooling systems and will have ahigher duty cycle.

A welder with a duty cycle of 150 amperes at 20per cent can produce 150A for just two minutes outof every 10 before the current level either falls orthe machine shuts down. This machine also mighthave a rating of 95A at 100%, which means it canweld continuously at 95A and not overheat.

To assess portable welder performance,Kondinin Group engineers operated the 13 units atmaximum output for 10 minutes using 3.2mmelectrodes and recorded output current and voltage(see Table 1).

Performance testsWhile some units shut down due to overheating,

many worked well for the entire period of testing.Although most output currents fell during thisperiod, most machines produced quality welds.

Kondinin Group engineers judged all welders ontheir ability to operate a range of welding rodscommonly used on farms. These included general-purpose E4113 electrodes (3.2mm and 4.0mm),AC700 3.2mm hardfacing electrodes (1855–A4),stainless steel 3.2mm electrodes (E316L–16) andE4111 3.2mm cellulose flux electrodes.

The engineers used the E4111 electrodesbecause these have a high open circuit voltagerequirement of 70 volts and can be difficult to strikeon some machines.


Make and model Rated Measured Average Average Average Open Duty cycle Current VRD Insulation Weight Country Price maximum maximum minimum output input circuit maximum at 100% fitted protectionE (kg) of origin (with GST)welding welding weldingB voltageB currentB voltageC currentD duty cycleD (amperes) (Class)current currentA (amperes) (amperes) (volts) (amperes) (volts) (amperes)

(amperes) (amperes)BOC Inverweld 110 110 116 104 27 13 32 110A at 50% 80 Yes IP23 4.2 Finland $1077

BOC Smootharc 130 130 138 133 25 20 62 138A at 35% 118 No IP21 5.5 China $326

CEA Rainbow 150 150 147 127 55 17 94 150 at 30% 100 No IP21 4.2 Italy $990

Cemont Colt S3200 125 133 114 21 13 67 125A at 15% 60 No IP21 3.8 China $539

CIGWeld Transarc 131i 130 130 115 24 14 104 130A at 40% 100 No IP21 5.2 Not listed $880

Esseti 150CS 150 139 111 39 16 116 150A at 30% 95 Yes IP23 4.4 Italy $1289

Euroarc 140 140 148 129 11 15 61 140A at 25% 85 No IP21 3.9 Italy $660

Fronius 1400* 140 130 120 27 15 95 140A at 35% 100 No IP23 4.2 Germany — *

Kemppi Minarc 120 120 121 109 24 13 31 110A at 50% 80 Yes IP23 4.0 Finland $1265

Lincoln Invertec V145S 145 145 136 37 22 10 145A at 60% 120 Yes IP23 5.9 Italy $1280

MigoMag 155 DCI 150 146 113 6 16 58 150A at 35% 110 No IP23 5.3 France $1045

TokenTools Miniarc 142 125 110 113 24 13 77 125A at 35% 70 No IP21 5.5 China $308

TWM IN2500 80 102 65 14 7 55 75A at 35% 50 No IP21 2.8 China $260

A. Measured using a 4mm electrode. B. In 10-minute test. C. Measured. D. Manufacturer’s rating. E. IP23 offers superior category of insulation to IP21. 1. Combination of average2. Across a range of welding electrodes tested. * This unit has been superseded by the 1500 model for $1628. ** Higher percentage scores indicate better performance.

TABLE 1 Inverter welder performance as tested by Kondinin Group

Clear operation: The CEA Rainbow(top) featured an arc–TIG selectorswitch with a setting especially for stainless (CrNi) electrodes, whilethe Lincoln Invertec had a ‘soft’mode for rutile flux (a mineral formof titanium dioxide) and stainlesselectrodes, a crisp setting for basicand cellulose flux electrodes.


evaluated as additional equipment was required for TIG welding such as a handpiece and shieldinggas bottle.

Many machines had a separate TIG function,which could be selected using a switch on the front panel.

Welders equipped with ‘lift-start’ TIG aresuperior to those with ‘scratch-start’ TIG, as the arc will start when the electrode is lifted off thework piece.

Keep in mind that aluminium TIG welding isnot possible with DC power.

Running on generatorsIn the past, inverter welders gained a bad

reputation for unreliability when operated off anextension lead or generator.

But now, some manufacturers guaranteemachines for operation in these situations. For example, the Lincoln Invertec V145S isguaranteed generator safe and can be poweredusing a 60m extension lead.

Most welders tested could operate off a sixkilovolt ampere (6kVA) generator.

Safety cut-offPrevious issues associated with low- or high-

supply voltages are now taken care of by thewelder’s computer, which will shut down themachine if the voltage is not within its workinglimits. If in doubt, check with the supplier beforebuying a unit.

The Kemppi Minarc had a key-operated switchon its rear allowing the VRD to be switched off.

Kondinin Group engineers expected the VRD tomake starting some welding rods more difficult butmost units performed well.

TIG welding was not testedWhile all units tested were capable of TIG

welding to some degree, this feature was not

Unique fittings (pictured top): The Esseti 150CS (left) was the onlyunit tested with large-diameterwelding lead bayonet fittings, asopposed to the more ‘normal’smaller fittings.


output current and time in operation after 10 minutes.


Annoying features (pictured bottom):Often simple features can becomeannoying. Rear-mounted powerswitches (left) are not visible to the operator and require reachingbehind the machine, compared withthose fitted to the front panel (right).

Performance tests: Kondinin Group engineer Josh Giumelli tested the welding performance of each of the 13 units. Inset: Examples of welds using (from left to right) hardfacing, 3.2mm and 4mm general purpose, stainless steel and 4111stovepipe electrodes (matching electrodes are pictured inset bottom, also from left to right) to test welder performance.

Tests showedproduct price wasno guarantee of performance.

10-minute Ease of striking Weld quality2

load test1 arc (% rating)** (% rating)**(% rating)**

88 70 65

88 80 80

97 70 90

69 80 70

84 65 75

77 75 70

94 75 75

94 90 90

90 60 70

94 70 80

75 85 75

91 70 70

55 20 30

FIGURE 1 How inverter welders work

Source and illustration: Kondinin Group.


How doinverterwelderswork?

How doinverterwelderswork?


Traditional welders use a transformer to lower theinput line voltage and boost the current to a levelsuitable for welding.

The frequency of Australian mains voltage is 50hertz alternating current (AC), which means thevoltage cycles from positive to negative 50 times a second.

While the alternating nature of AC current isessential to create a magnetic field and allow thetransformer to operate, it is not very efficient at50Hz, with up to 50% of electricity wasted astransformer heat.

A transformer needs to be built heavily towithstand heat and portability is compromised as a result.

The result is a steady and strong arc whichconcentrates heat at the electrode tip.

Positive versus negative electrodesMost DC welding is performed with a

positive electrode.

A negative electrode produces a thinner, deeplypenetrating weld as heat is concentrated in thework instead of within the electrode tip.

This type of electrode is more suited to flat-position welding.

Smart electronics help weldsA ‘hot-start’ function is common — this

device momentarily boosts current to assist arc initiation.

To prevent sticking electrodes, most units willshut down when they detect a short circuit.

Range of electrodesMore advanced features found on some

portable machines help the user weld withdifferent electrodes.

For example, the Lincoln V145S inverter weldertested has a ‘soft’ mode for rutile flux and stainless-steel electrodes.

In addition it has a ‘crisp’ mode for basic andcellulose flux electrodes.

The CEA Rainbow 150 has a special setting forCr–Ni (stainless) electrodes.

A sophisticated toolThe inverter welder uses far more sophisticated

electronics including microprocessor control to produce a more versatile welding unit (see Figure 1).

Rectifiers enable the transformerto produce less heat, which meansthe welder can be packaged for portability.

To increase the current using a smalltransformer the inverter welder uses a combinationof rectifiers (which ‘chop off’ the negative half of the voltage cycle), inverters and switchingcircuits to boost frequency to tens of thousands of cycles.

As a result, the transformer operates moreefficiently, producing less heat and allowing theinverter welder to be packaged for portability.

Flexibility a bonusThe rectified welding supply in an inverter

welder is direct current (DC), which has severaladvantages over AC welders.

Vertical and upside-down welds are easier to produce when the electrode is connected to the positive terminal and the work to thenegative terminal.



The microprocessorcontrol inside aninverter welderadjusts welding

current and voltageto best suit

different situationsand electrode types.

This space is deliberately blank

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(c) Farming Ahead

R E S E A R C H : R E V I E W S I N V E R T E R W E L D E R S

Engineers’ commentThe BOC Inverweld 110 is a sleek and compact

inverter welder.

But tests showed it lacked enough current for fullpenetration on the four-millimetre electrodes.

Hardfacing and 4111 electrodes were easy to usebut stainless and 4mm electrodes were a littledifficult to start. Output current was extremelystable at all times.

Price$1077.32 (includes tax).

BOC INVERWELD 110

Switchable voltage-reductiondevice.

Tungsten inert gas function.

Compact.

Front power switch.

Terminal polarity labelling.

No handle (strap only).

Radio interference.

10-ampere plug.

Worst features

Best features

Engineers’ commentThe unit had an excellent all-round performance

with adequate penetration on all welds and a highweld deposition rate.

A small hesitation when using the 4mmelectrodes made striking an arc a little difficult butall other electrodes start and run well. At this price,it represents an excellent value entry-level machine.


Engineers’ commentWeld quality was brilliant with low spatter and

excellent penetration.

The arc was easy to start and there was littledifference between using 3.2mm or 4mmelectrodes. The welder was a pleasure to use.

Price$990 (includes tax).

CEA RAINBOW 150

Compact and well-built.

Lift tungsten inert gas function.

Heavy-duty lead.

Safe to use with 60-metreextension lead.

No shoulder strap included.

Radio interference.

Worst features

Best features

Choice governed bysuitability for the jobKondinin Group engineers judged all 13 inverter welders on their ability to operate a range of welding rodscommonly used on farms. The units were tested at maximum output for 10 minutes using 3.2-millimetreelectrodes and the output current and voltage were recorded.

BOC SMOOTHARC 130

Terminal polarity well marked.

Switch at front and acomfortable handpiece.

Value for money

Large fan.

Best features

10-ampere plug.


No tungsten inert gas function.

Worst features


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(c) Farming Ahead

Engineers’ commentA simple but capable welder which produced

consistent welds after easy starting but poorpenetration when using 4mm electrodes.

This welder represents value for money and is onlylet down by a lower duty cycle. An excellent choicefor farmers not welding continuously.


Terminal polarity labelling.

Rear power switch.


Low duty cycle.

CEMONT COLT S3200

Lightweight yet robust.

Simple and easy to use.

Value for money.

Best features

Engineers’ commentAll welds were even and well formed, except

when using 4mm electrodes where penetrationwas low.

The welder has a soft and gentle arc but startingthe 4111 electrodes was a little difficult.

A simple, compact and easy-to-use welder.


Compact and solid build.

Simple to use.

High duty cycle.

Low radio interference.

Best features

I N V E R T E R W E L D E R S R E V I E W S : R E S E A R C H

Engineers’ commentAn impressive output current gave excellent

penetration and deposition rates.

But weld quality was affected by a fluctuatingoutput current.

The welder performed well in the 10-minute test but was difficult to start with the 4111 electrodes.


EUROARC 140

Output current performance.

Face panel protects controls.

High weld deposition rate.

TIG function.

Best features

Fitted with a 10-ampere plug.

No shoulder strap.

Rear power switch.

No tungsten inert gas function.

Worst features

No handle and poor qualitypower lead (3 x 1.5mm2).

Rear power switch.

Lightweight tungsten inertgas switch.

Radio interference.

Worst features

Engineers’ commentThe Esseti 150CS produced its best results when

operated ‘flat-out’ but output current droppedduring the 10-minute test.

An unstable output current produced slightlyuneven welds but output was high and penetrationwas satisfactory.

The 4111 electrodes were more difficult to startwhen the using voltage reduction device (VRD).


ESSET I 150CS

Key-operated VRD.

Tungsten inert gas function.

Heavy-duty power lead.

High current and penetration.

Best features


High open circuit voltage (116V).

Rear power switch.

Cost.

Worst features

Worst features


CIGWELD TRANSARC 131i


Engineers’ commentAn excellent, high-end and compact machine

that produced perfect, even welds with highpenetration and deposition rates.

All electrodes were easy to start and output currentwas steady.

PriceThe unit has been replaced by the 1500 model at

$1628 (includes tax).

FRONIUS 1400

All-round performance.

Robust and compact.

Weld quality.

High duty cycle.


Rear power switch.

Price.

Worst features

Best features

Engineers’ commentA solid performing welder that just lacked

enough current to produce full penetration whenusing 4mm electrodes.

Both 4mm and 4111 electrodes were difficult to start.

But performance in the 10-minute test was excellent.


KEMPPI MINARC 120

Compact and well built.

Performance under load.

IP23C insulation rating.

Quality leads.

Guaranteed generator safe.

Fitted with a 10-ampere plugbut drew up to 24A.

Fiddly rear switch.

Difficult-to-read terminal polarity.

Worst features

Best features

Engineers’ commentWhile expensive, the Lincoln Invertec V145S

produced excellent penetration on all welds andwas a standout performer with the 4mm electrodes.

Kondinin Group engineers found it difficult attimes to strike an arc when the voltage reductiondevice was on, especially with the 4mm electrodes.

Although the welder was the largest tested, it wasnot heavy.


L INCOLN INVERTEC V145S

Construction quality.

Performance with 4mm electrodes.

VRD can be switched off.

Soft, crisp and tungsten inertgas function.

Generator-safe guarantee.


Power switch on rear.

Larger size.

Expensive.

Worst features

Best features

Engineers’ commentThis welder is rubbish. Spend the extra $48 and

buy the Tokentools Miniarc 142.


TWM IN2500

Compact and lightweight.

Kit form with leads and rods.

Performance and low duty cycle.

Cannot reliably weldelectrodes more than 2.5mm.

Fitted with a 15-ampere plugbut draws 6–7A.

Worst features

Best features

Farming Ahead February 2007 No. 181 www.kondinin.com.au24



Manufacturer Phone Email and web site

BOC 131 262 [email protected]

CEA Contact local retailers [email protected]

Cemont Contact local retailers [email protected]

Cigweld 1300 654 674 [email protected]

Esseti (02) 6686 3666 [email protected]

Fronius (03) 9466 4060 [email protected]

Kemppi (02) 9605 9500 [email protected]

Lincoln (02) 9772 7222 (NSW) www.lincolnelectric.com.au/knowledge/askus/(07) 3271 3000 (Queensland) www.lincolnelectric.com.au(03) 9543 9399 (Victoria)(08) 9277 8744 (WA)

Migomag (03) 9312 4999 [email protected]

Tokentools (02) 8208 3363 [email protected]

Contacts

RESEARCH ENGINEERS Ben White (pictured from left), Josh Giumelliand Tim Andrew tested and evaluated the inverter welders for this report.

TEST EQUIPMENT SUPPLIERS BOC Gas and Gear, WA, and Chris Birchall(BOC Inverweld 110 and Smootharc 130); Burnback Welding, WA (CEARainbow 150, Cigweld Transarc 131i, Kemppi Minarc 120, Migomag 155DCI); Gentronics, WA (Cemont Colt S3200, Esseti 150CS, Fronius 1400);Neil Bowers, Lincoln Electric, WA (Lincoln Invertec V145S); KondininGroup bought the Tokentools Miniarc 142 (from www.tokentools.com.au)and TWM IN2500 (www.ebay.com.au). WIA was unable to supply WIAand Miller welders at the time of testing.

Engineers’ commentKondinin Group’s test engineers rated highly

this unit’s welding performance as it producedhigh deposition rates and was easy to start.

High current output ensured full penetration on all welds but current fell away during the 10-minute test.


MIGOMAG 155DCI

Heavy power lead.

High current output.


Guaranteed generator safe.

Best features

Engineers’ commentWhile a fluctuating output current led to less

than perfect weld beads there was no doubt aboutthis welder’s value for money.

Penetration performance was poor when testedwith 4mm electrodes.

But the welder was excellent during the 10-minute test.

Kondinin Group engineers believed a small outlay would reward owners with a capable welder.


TOKENTOOLS MINIARC 142

Excellent value for money.

Simple machine.

Supplied with case and accessories.

Reasonable performance.

Best features

No leads included.

Current drops off under high-duty cycle work.

Rear power switch.


Radio interference.

Worst features

Rear power switch.


Light build.

Radio interference.

Fluctuating current led touneven welds.

Accessory quality.

Worst features

research report: tested: inverter welders€¦ · tokentools 142 and the $539 cemont colt s3200 and...

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