WTT8-B1 Single Function Time Relay with Delayed Drop-Out
The WTT8-B1 runs one timing job. The output is picked up while the supply is present, and when the control circuit opens the contact stays closed for the set time before it drops out. That is the run-on a fan needs after a motor stops, or the post-purge a burner needs after the flame goes out.
Delay OFF, Nothing Else to Set
There is no function selector on the face. A builder who knows the panel needs a drop-out delay fits this part and sets two dials, which removes the chance of a mode selector being left in the wrong position on site. The B version is the delayed disconnection type, and the same frame is offered as an A version for power-on delay and as two contact versions for panels that need a second pole.
Setting It From the Face
The upper potentiometer picks the range, with the scale printed from 1 second to 10 days around the dial, and the lower one trims the time inside that range from 10% to 100%. Setting deviation is 10% and repeat accuracy is 0.2%, so the tenth cycle opens as close as the first. Both dials are read and changed with a screwdriver through the front, without removing the module from the rail.
Supply, Contact and Reset
A1 and A2 take AC or DC from 12 to 240V at 50 or 60Hz, with a tolerance of -15% to +10% and a burden of 0.09 to 3VA on AC or 0.05 to 1.7W on DC. The S terminal beside the supply pair takes the control circuit. The output is a single changeover contact on 15, 16 and 18 rated 16A at AC1, switching 250V AC or 24V DC, with a minimum breaking capacity of 500mW for low level signals. Reset takes 200ms at most.
Panel Fit
The body is one 18mm module of 90mm depth and clips to a 35mm rail. The face is IP40 and the terminals IP20, overvoltage category III at pollution degree 2, rated -20°C to +55°C. Terminals take one 2.5mm² or two 1.5mm² conductors at 0.4N·m. Mechanical life is 10 million operations and electrical life 100,000 at AC1. A green lamp shows the supply and a red lamp shows the output state. The body carries CE and CCC marking. Send your delay time, supply voltage and quantity to WTAIELE for a quote.
