FAQ - Transformers

Transformers general

Can I place higher or lower loads on the transformers (capacity utilisation)?

Can I place higher or lower loads on the transformers (capacity utilisation)?

A higher load will cause the transformer to overheat. This could trigger the thermal breaker or thermal fuse. Transformers with a thermal fuse will then be defective.

Transformers may be placed under lower loads. The minimum load for conventional transformers should not fall below 75 %, as the output voltage will build up too quickly, decreasing the service life of the bulb.

In the case of electronic transformers, the minimum load is lower, as the output voltage does not build up as quickly. e.g. 20 W minimum load for 70VA transformers, 35W for 105 VA, 50 W for 150 VA. Always observe the manufacturer's specifications!

For instance, an overvoltage of just 5 % can shorten the service life of the bulbs by up to 50 %. For this reason, it is recommended to keep the transformers at 100% of capacity at all times so that the highest possible service life is achieved.

Can transformers be used outdoors?

Can transformers be used outdoors?

Transformers can be used outdoors as long as they are protected from water (under roofing, etc.).

Conventional and electronic transformers are available with additional moisture resistance specifically for use in moisture-prone areas.

Paulmann items 97797 and 98759

What does TC 75°, TA 45°C mean on the transformers?

What does TC 75°, TA 45°C mean on the transformers?

TC indicates the permissible housing temperature; TA the max. permissible ambient temperature.

The output voltage from the transformer is too low or too high?

The output voltage from the transformer is too low or too high?

These readings may be the result of using measuring devices that are not suitable for measuring the high operating frequency of electronic transformers (40,000 Hz). These measuring devices are only suitable for measuring conventional transformers; in the case of electronic transformers, they generally lead to false results. The measuring devices required are true RMS measuring devices with a frequency limit of >80,000 Hz.

 

 

 

Transformers LED

Which transformer should I use for LED lights?

Which transformer should I use for LED lights?

There are various types of electronic ballasts for use with LED light sources.

LED transformer
This is a conventional transformer with a metal core that supplies a 12 VAC voltage. These transformers are suitable for all 12 V retrofit bulbs (replaceable bulbs that have standard fittings and are modelled on the design of the 12 V halogen bulbs).

LED power supply DC
These ballasts provide 12V direct current (DC) and are suitable for lighting fixtures without replaceable bulbs, with a type plate that specifically prescribes operation with 12 VDC voltage.

LED driver
These ballasts supply a constant current of 350 or 700 milliamperes (mA) (depending on the model) with varying voltage (V). LED drivers are for lighting fixtures without replaceable bulbs and with a type plate that specifically prescribes operation with constant current.

 

Paulmann LED bulbs are retrofit bulbs. That means that no special ballasts are necessary, provided that the overall power consumption of the bulbs used falls within the power range of the transformer used.

Would you like to retrofit your lighting with LEDs?

 

 

Electronic Transformers

Why does the light flicker / Why don't I get 100% of the potential illumination?

Why does the light flicker / Why don't I get 100% of the potential illumination?

Why is/are the last light(s) dimmer than the others?

The cable length for electronic transformers is limited to max. 2 meters.

The following problems can occur if the cable length is any longer:

1. Increased interference, as the cable acts as a transmitting antenna (transformer operates in the high frequency range)

2. Skin effect - the full cross-section of the cable is no longer available for conducting the current. The current is forced into the outer areas of the cable. Less current flows through the middle of the cable, and the light becomes much dimmer.

Why are there two primary (230V) connectors?

Why are there two primary (230V) connectors?

The two primary connectors are parallel inside the transformer. If, for instance, two transformers are connected to a ceiling outlet, one of the transformers can be directly connected and the second transformer can be supplied from the second primary clamp.

Why is the cable length of electronic transformers limited to 2 metres?

Why is the cable length of electronic transformers limited to 2 metres?

The following problems come up in the case of longer lengths of cable:

The interference increases, as the low voltage cables act as transmitting antennas (transformer operates in high frequency range).

High operating frequency leads to the SKIN EFFECT. This means that the full cross-section of the cable is no longer available for conducting the current. More of the current is forced into the outer areas of the conductor. Less current flows through the middle of the cable. As a result, there is a disproportionally high drop in voltage over longer cable lengths and the light becomes much dimmer. With wiring in the form of a star (transformer in the centre), 4 metres of cable can be supplied. If this is not sufficient, it will be necessary to switch over to a conventional 50 Hz transformer.

Why is the start-up of the electronic transformer delayed?

Why is the start-up of the electronic transformer delayed?

The transformer performs a soft start. The converter "recognizes" a surge of power at start up and counters it with the short-circuit current limitation, or in other words, the switch-on power is limited, but not to zero. The remaining switch-on power is sufficient to warm up the filament of the bulb. The short-circuit current limitation is continuously phased down until the full brightness is achieved. This start behaviour has a positive effect on the service life of the bulb.

An overload on the electronic converter (transformer) may also cause an excessive delay.

For electronic converters from Paulmann, the soft start should not last more than 1.5 seconds.

What happens if the supply falls below the lower capacity limit of an electronic transformer?

What happens if the supply falls below the lower capacity limit of an electronic transformer?

The light begins to flicker or the light goes out completely. Reason: Self-protection, as the transformer switches off when idle.

 

 

Conventional Transformers

What type of microfuse is required?

What type of microfuse is required?

The fuse class is always listed next to the fuse. The start-up power surge can trigger the fuse if the wrong type of fuse is in use. The switching characteristics of the microfuse must be "time-delayed" (e.g. T 1.6A). Do not use fuses designated M, MT, or F, as these will always quickly fail.