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A medium priced generator set from eBay

This article documents issues with a 2500W generator set purchased on eBay from seller AGR Machinery.

Fig 1:

Fig 1 shows the generator set. on the side facing is the switchgear panel with motor switch, voltmeter, circuit breaker and two 15A outlets.

The generator is supplied without oil, ie none in the sump and none in the packaging. Fortunately, there was some suitable oil on hand. These should not be run on multi-grade car engine oil.

The machine was oiled and fuelled and given a test run for half an hour with no load. The engine started first pull, and ran very smoothly (remember though it is not idling, it is running at 3000RPM for 50Hz).

At the end of this test run, the electrical sockets were checked, and the right hand one had no connectivity from the earth pin to the chassis. On looking behind the control panel, the cover was detached and the panel wiring exposed. It could be seen that the earth wire was not connected to the right hand outlet, but had come adrift.

Fig 2:

Fig 2 shows behind the control panel after it was unbolted from the roll cage.

The earth wire is clearly not inserted in the right hand outlet, and the ends of the three conductors are twisted together and soldered. Wires soldered as this are a risk to become loose in screw terminals, as the lead in the solder cold flows under pressure over time, and the screw becomes loose. Worse in a machine such as this subject to vibration.

 This machine as had half an hours use at no load, and ALL of the terminal screws on the outlets are loose, and the earth wire completely fallen out of one outlet. All of the power wiring had tinned ends on the wires.

Fig 3:

So, a check of the mechanical fastness of all connections is warranted. You guessed it, the screw terminal above was loose. It could not be tightened without bending the tab as the switch to the left prevents effective screwdriver access. The DC circuit breaker was also loose. The screws securing the AC circuit breaker were loose.

Notice the bent clip in the foreground, a probable contribution to the protective cover coming off. Two more clips are similarly twisted.

Fig 4:

Fig 4 shows the installed circuit breaker, which is described as an ELCB, also known as an earth leakage circuit breaker, residual current device (RCD, or Safety switch). Most informed people will notice that it does not have the test facilities usually found on an ELCB.

Fig 5:

Fig 5 shows the rear of the circuit breaker. It is categorically not an ELCB, it is only in the active circuit so it cannot detect earth leakage, it is an ordinary single pole circuit breaker.

Rework

All of the tinned ends were cut off, and where necessary due to length, new equivalent conductors fitted. The terminal tunnels were fairly small for the device current rating, so the stripped wire ends were twisted and inserted into uninsulated bootlace connectors, and terminated in the screw terminals.

Access to the terminal screws was obstructed by the circuit breaker, and some parts of the plastic escutcheon moulding. The breaker needed to be removed and the plastic mouldings were ground out to give access to the earth terminal screws.

Since this generator will be used with multiple appliances of Class II, the neutral was bonded to the earth conductor to allow the effective use of a portable RCD device.

Radio Frequency Interference

A minimal test was conducted of the radiated emissions on 7MHz. Whilst the generator is not intended for radio operations, readers have expressed an interest in its noise performance.

Test 1

A portable SSB receiver with a 1m whip was used to monitor emissions from the generator itself with a 20m 3 core cable laid on straight on the ground. Some evidence of ignition noise was heard when the whip was located closer than 300mm to the spark plug lead. At 1m distance from the genset, no interference was heard, nor was any heard when the whip was laid against the cable.

Test 2

A 20m lead was plugged into the machine and powered up. The 20m lead was laid out on the ground under a 40m half wave dipole. The background noise level in this location is very low, and on test, reading 1 segment on the TS2000 S meter. There was no perceptible change in noise with the generator running, both with no load and a 1kW load.

Residual issues

Nowhere on the machine is there claim of compliance with the relevant Australia / New Zealand standard(s).

No current rating for the DC output in the documentation or on the machine or the eBay advert. The DC circuit breaker is rated at 10A (not visible from the outside). On test, the machine charged a well charged lead acid battery (on a ride on mower) at 4A.

The plastic cover behind the control panel probably needs rework so that it remains attached.

The seller cheerfully offered a small refund to address some of these issues, and it was accepted.

Conclusions

Links

Changes

Version Date Description
1.01 07/12/2011 Initial.
1.02    
1.03    

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