Wired but failed!

As an experimental trial just wired mechanical 24V relays to control family use vacuum cleaner that is a replacement device for the vacuum system in our new laboratory, but in vain. Just an information from the professional about 24V signal wiring on the working chair was not enough, because the current sauce was not specified, alternative current or direct one if they were 24V?
Net surfing in the Web sites seeking the information about the designing of the electric parts proved there exist actually two types with the same sizes and also the 24V signal source must be defined?

Just trying it anyway when busy for the preparation before starting for the attendance to the meeting at noon, I failed!
The intermediate contact terminal was just vibrating like a buzzer, informing that the mechanical relays were designed for direct current and the signal outlet were alternative current.
Though I should ascertain the designing concept before doing that, no printing information was found on relay plastic case, just only 24V was written.

Once the inconvenience and the reason for it have been revealed as the actual result, I have to countermeasure for that by applying the rectification and smoothing circuitry preventing buzzer like vibration phenomena on the intermediate terminal in DC designed mechanical relay parts.
Yes, this is today's obliged tasks in my villa, some rectifier and capacitors would be found in my junk box?