50/60 Hertz 220-230vac Tranformers

Thread Starter


Joined Nov 10, 2009
We have just completed a major CCTV system installation in Asturias Spain consisting of approximately 45 PTZ dome cameras. After two months of operation we are now experiencing the 1 amp transformer fuses are blowing frequently . Each camera location has a dedicated Altronix open frame 100VA transformer operating at 24vac 50 hertz between 220 and 230 volts a.c. (T24130D). The transformers are hot to the touch yet serves on the single pan tilt and zoom camera. The manufacturer states the unit is rated at 4.61 ampa @ 24vac.

Can anyon please assist me or offer any suggenstions;

Thanks in advance for your help


Joined Jul 17, 2007
Datasheet for the transformer: http://www.altronix.com/p_data/DST24130D.pdf

Is the fuse on the output of the transformer? Are they slow-blow fuses?

You should have a 1/2A slow blow fuse on the transformer primary winding.

Are the installations inside or outside? If outside, the transformer needs to be enclosed, but that will cause a build-up of heat unless the enclosure is metal, and the transformer is bolted to the enclosure.

What is the current rating for the PTZ cameras?

Duane P Wetick

Joined Apr 23, 2009
My calculator tells me that 24 x 4.61 = 111 not 100 VA. What is the amp rating of the 45PTZ camera; nameplate rating? Also, some transformers give the VA @ 60 HZ. At 50 HZ. you may have to derate; 5/6 or 0.83 X 100. Also, slo-blo fuses must be used for transformer inputs and the environmental factors must be considered as Sarge recommends.

Hope these hints help...DPW