ERECTA SWITCH® by Compac Engineering
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50-NP-AC5 — NistorPac Solid State Relay — 1-Pack

Non-latching solid state AC relay, 24–240 VAC, 5 A with heat sink

SKU 50-NP-AC5 · Stock 5501432 · 1-Pack
1-Pack5-Pack
Net price — per unit · quantity breaks
QuantityPrice
1–10$47.74
11–20$45.83
21–49$42.96
50–74$38.20
75–99$33.41
100+$31.02
As low as $31.02 per unit. Prices from the current price file; no minimum order.
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Specifications
Switching modeS.P.S.T., normally open
Voltage range24 – 240 VAC, 50–60 Hz
Load rating — no heat sink0.75 A (inductive / tungsten / resistive)
Load rating — with heat sink5.0 A
Maximum surge15 A
Minimum load0.1 A
Sensor circuit resistance300 ohms max (other than load)
Sensor current2 mA typical
Voltage loss2 VAC typical
Leakage through load terminal< 6 mA
Power dissipation0.92 watt per amp switched
Dimensions1.500″ × 1.500″ × 0.955″ (38.10 × 38.10 × 24.25 mm)
Ambient temperature0 – 120 °F
TerminalsEurostyle® screw type
ComplianceRoHS compliant

Product Description

The 50-NP-AC5 NistorPac is a solid state AC switching relay designed expressly for OEM use. Reed switch sensors deliver a reliable, low-power contact closure but cannot directly drive pump motors, solenoids or high-current loads. The NistorPac bridges that gap: the sensor pilots the relay, and the relay switches the load. In other words it lets a reed switch sensor handle a bigger job than it can do by itself.

It has no moving parts, so it is silent, cannot suffer contact wear, and does not arc. It is a continuously powered device: in standby it draws a tiny amount of current — typically less than 0.001 A. When the sensor closes, supply voltage is switched through to the lamp, solenoid or motor, and the load stays on for exactly as long as the sensor circuit is complete.

Wiring

Eurostyle® screw terminals accept two wires from the voltage source, two from the load device and two from the sensor. Load connects to terminals A and F, line voltage to B and E, and the sensor to C and D. Control of the load is accomplished simply by completing and interrupting the sensor circuit between C and D. Optional wiring ferrules (50-BP-F series) make terminal block wiring easier. Use AWG 20 minimum for sensor circuits and AWG 18 minimum for line and load circuits, and fuse line and load circuits to the applicable equipment codes.

Heat management

NistorPacs dissipate roughly 0.92 watts per amp switched, and only while the load is on. Below 0.76 A the built-in heat sink is sufficient. Above that the relay must be attached to a supplemental heat sink or any cool metal surface of sufficient area to keep it from overheating — single-side area in square inches is (amps × 1.25)² on 1/16″ aluminium, with silicone grease at the interface. Mount away from high-heat sources and allow airflow in tight enclosures.

What you can drive it with

Any dry contact or passive SPST sensor will pilot a NistorPac — reed switches, float switches, bimetallic temperature switches, flow switches, magnetic contacts, thermostats and pressure switches. That makes it useful well beyond liquid level: thermal shutdown interlocks that cut power to a heating element on over-temperature, door and panel interlocks, pressure-triggered compressor or alarm stages, flow verification circuits, HVAC damper and blower control, and light-duty feeders or mixers driven from a simple contact closure.

← All Series 50 relays

Frequently Asked Questions

Common Questions About This Product

What does the 50-NP-AC5 do, and why would I need one?

It is a solid state AC switching relay for OEM equipment. A reed or float sensor gives a reliable, low-power contact closure but cannot directly drive a pump motor, solenoid or other high-current load. The 50-NP-AC5 bridges that gap: the sensor pilots the relay, and the relay switches the load — letting a sensor handle a bigger job than it could by itself.

What can I use to control the 50-NP-AC5?

Any dry contact or passive SPST sensor will pilot it — reed switches, float switches, bimetallic temperature switches, flow switches, magnetic contacts, thermostats and pressure switches. That makes it useful well beyond liquid level: thermal shutdown interlocks, HVAC damper and blower control, and light-duty feeders or mixers driven from a simple contact closure.

What load can the 50-NP-AC5 switch?

Series 50 relays switch line-voltage AC loads, and the exact voltage range, continuous load rating, maximum surge and minimum load are listed in the specification table on this page — they differ between models, so read the table for the one you are specifying rather than assuming. Note there is a MINIMUM load as well as a maximum: below it the relay may not switch cleanly.

How do I wire the 50-NP-AC5?

Eurostyle&reg; screw terminals take three pairs: line voltage, the load device, and the sensor. The load connects to terminals A and F, line voltage to B and E, and the sensor to C and D. Control is simply completing and interrupting the sensor circuit — the load stays on for exactly as long as that circuit is complete. Observe polarity conventions for your line and load circuits and fuse both to the applicable equipment codes.

Does the 50-NP-AC5 need a heat sink?

It depends on the current you are switching, and the threshold is on the specification table on this page. The relay dissipates heat only while the load is on. Below the stated threshold the built-in heat sink is sufficient; above it, the relay must be attached to a supplemental heat sink or any cool metal surface of adequate area to keep it from overheating.

What are the advantages over a mechanical relay?

It has no moving parts, so it is silent, cannot suffer contact wear, and does not arc. That matters in OEM equipment expected to cycle for years without service, and in enclosures where arcing contacts are undesirable. ⚠ Note it is a solid state device: it passes a small leakage current through the load terminal even when off, which the specification table quantifies — check that your load tolerates it.