Kapeesh Electricals

It’s part of the UNI 901 PHT series. “PHT” stands for Phase Angle High Power Thyristor / SSR – analog phase‐angle controlled SSR. 

“44” is likely the input voltage code (control / input specification), often meaning 4‑20 mA input with 100 Ω impedance for that input type. 

“50” is the load current rating: 50 Amps. 

“420” I believe refers to the output voltage / isolation rating (or part of the series where the SSR can handle up to 420 VAC or is designed around that in some way). 

“AL5” seems to be the body/insulation or design code (material, mounting, heat‐sink version) used by Unison. 

Model: UNI 901 RDA 60 90 01 CU2

Type: Random Switching Solid State Relay

Input (Control): 4–32 VDC / 4–16 mA

Output: 24–600 VAC

Current Rating: 90 Amp

Frequency: 47–63 Hz

Isolation:

• Body insulation: 6 kV

• Input–Output insulation: 8 kV

Surge Protection: 2700 Vrms built-in

PIV: 1600 Vpk

Heat sink: Usually used with B-48 heat sink + DIN rail

“UNI” = brand prefix for Unison.

“807” = series/model family (the “807” SSR series).

“PMDD” = designation for “MOSFET DC-to-DC Solid State Relay” (in Unison’s nomenclature). See listing for 807 PMDD series.

“100” = probably the maximum output voltage (in this case 100 VDC).

“08” = rated current (8 A).

“01” = revision or variant number.