OMRON H3BF-N8 OMRON Timer Relay

H3BF-N8, Recycle ON-OFF Cycle Timer Relay, 8-pin socket-mount type, AC/DC wide-voltage design, for industrial cyclic timing. Applications include intermittent motor start-stop, lighting cycling and periodic equipment control.

1. Décodage du modèle

H3BF: Nom de la série, Dual-setting cycle timer relay (independent ON-time and OFF-time adjustment)

N: Universal power supply: AC24-240V / DC12-240V

8: 8-pin round socket (Matching base: P2CF-08)

2. Spécifications principales

Logique de fonctionnement

1. Power on → Output energized, start timing T1 (ON-time)
2. T1 timeout → Output de-energized, start timing T2 (OFF-time)
3. T2 timeout → Output re-energized, restart T1, infinite cycle

✅Independent adjustment for ON duration and OFF duration, which is the key feature of H3BF-N8.

3. Définition des broches (8-épingle)

Épingles 2-7: Power input, no polarity distinction for AC & CC

Épingles 1-3-4: Sortie SPDT: Pin1=Common, Pin3=NO(Normalement ouvert), Pin4=NC(Normalement fermé)

Épingles 5-6: External reset terminals. Short-circuit pin5-6 to force timer reset.

Note: Do NOT keep pins 5-6 permanently short-circuited. Timer stops timing while shorted.

4. Dépannage courant
5. No cyclic action: Verify T1/T2 are not set to minimum; check accidental short-circuit on external reset 5-6; confirm power supply.
6. Timing inaccuracy: Confirm time unit range (s/min/h); avoid power supply fluctuation.
7. No contact switching: Load exceeds 5A rating. Use auxiliary relay for load expansion.
8. Sélection alternative
9. Original unit: H3BF-N8 (Discontinué; mostly stock / second-hand units on market)
10. Alternatives nationales:

DH48S-S (8-pin cycle timer, base compatible with P2CF-08)

ZYS48-S, similar timing parameters and pin-out

⚠️Notice: Some domestic versions omit external-reset function. Confirm reset function before ordering if pins 5-6 reset is required.

6. Second-hand Unit Inspection Checklist
7. Contrôle visuel: No burn marks on housing; no corrosion on socket pins.
8. Test de mise sous tension: Set short timing T1=5s, T2=5s; verify alternating ON-OFF switching.
9. External-reset test: Court 5-6 temporarily; timer resets immediately and resumes after release.
10. Multimeter test NO/NC contact continuity to rule out contact burnout.

H3BF-N8 Text-Based Wiring Diagram + DH48S-S Comparison

Base: P2CF-08 (8-pin round base). Pin numbering clockwise facing socket openings: 1-8.

📌H3BF-N8 Pin Assignment

Scheme1: Basic cycle (no external reset, épingles 5-6 left open)

1. Connect power L/N to pin2 and pin7.
2. Load circuit: Live wire → pin1(COM); pin3(NON) connects to contactor coil / borne de charge; load other terminal returns to neutral.
3. Leave pin5 and pin6 unconnected, floating.

Cycle starts upon power-on: Output energized for T1, de-energized at T1 expiry, count T2, re-energized at T2 expiry and repeat cycle.

Scheme2: Manual reset via push-button

1. Power to 2-7; load wiring 1-3 unchanged.
2. Connect a normally-open push-button across pin5 and pin6. Pressing button short-circuits 5-6 for immediate reset; cycle restarts after button release.

⚠️Critical Reminders:

No polarity for DC supply on pin2-7, wide-voltage tolerant.

External reset is for momentary short only. Continuous short on 5-6 freezes timer permanently.

Max contact rating 5A resistive load. Add intermediate relay when driving contactors or heavy loads.

Timing Sequence

Power-on → Output energized, T1 ON-timing running;

T1 elapsed → Output de-energized, T2 OFF-timing running;

T2 elapsed → Output energized, repeat cycle.

📊Comparison: H3BF-N8 vs DH48S-S (Remplacement domestique)

⚠️Notes de remplacement:

1. DH48S-S has no universal AC-DC model. Match coil voltage with site supply voltage.
2. If external reset is required, confirm DH48S-S model supports reset; cheap simplified units render pin5-6 ineffective.
3. H3BF-N8 starts cycle immediately after power-on; DH48S-S shares identical power-on trigger logic.

🔧Second-hand H3BF-N8 Quick Power-on Test Procedure

1. Install onto base; feed AC220V to pin2-7.
2. Set T1=5s, T2=5s; keep pin5-6 floating.
3. Mise sous tension: Observe relay click switching and indicator toggle approximately every 5 secondes.
4. Momentarily short pin5-6 with wire: Timer resets instantly; cycle resumes after wire removal.
5. Multimeter test continuity of NO/NC contacts for no burnout.

OMRON H3BF-N8 Temperature Parameters (Official Datasheet)

1. Température ambiante de fonctionnement (powered): -10℃ ~ +55℃, pas de glaçage
2. Température de stockage (unpowered): -25℃ ~ +65℃, pas de glaçage
3. Operating humidity: 35%-85%RH, condensation interdite

Temperature-induced timing deviation within -10～+55℃: Max ±2%FS (plus ±10ms error for short-time ranges).

Field Application Notes

1. Avoid cabinet internal temperature sustained above 50℃ in summer due to poor ventilation. Timing accuracy degrades near upper limit 55℃.
2. Icing and condensation are forbidden. Below -10℃, incorrect timing or failure to start may occur.
3. Protection contre la pénétration: IP40 (front panel only), sides and rear not dust/water resistant.

Reference vs Domestic DH48S-S

H3BF-N8: -10~+55℃

Most DH48S-S domestic versions: 0~+50℃, inferior low-temperature performance versus original OMRON unit.